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Mechanisms of cooperativity and allosteric regulation in proteins

Published online by Cambridge University Press:  17 March 2009

M. F. Perutz
M. F. Perutz
Affiliation:
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK
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AUosteric proteins control and coordinate chemical events in the living cell. When Monod conceived that idea he said that he had discovered the second secret of life. The first was the structure of DNA. The theory as published by Monod et al. (1963) was concerned chiefly with cooperativity and feedback inhibition of enzymes, such as the inhibition of threonine deaminase, the first enzyme in the pathway of the synthesis of isoleucine, by isoleucine, and its activation by valine. Two years later the theory was formalized by Monod et al. (1965).

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Research Article
Information
Quarterly Reviews of Biophysics , Volume 22 , Issue 2 , May 1989 , pp. 139 - 237
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Copyright © Cambridge University Press 1989

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References

Abelson, P. H., (1954). Amino acid biosynthesis in Escherichia coli: isotopic competition with 14C glucose. J. biol. Chem. 206, 335–343.CrossRefGoogle Scholar
Almassy, R. J., Janson, C. A., Hamlin, R., Xuong, N.-H. & Eisenberg, D. (1986). Novel subunit-subunit interactions in the structure of glutamine synthetase. Nature 323. 304–309.Google Scholar
Amit, A. G., Mariuzza, R. A., Phillips, S. E. V. & Poljak, R. J. (1986). Three-dimensional structure of an antigen-antibody complex at 2·8 Å resolution. Science 233. 747–753.CrossRefGoogle ScholarPubMed
Antonini, E. & Brunori, M. (1971). Hemoglobin and Myoglobin and their Reactions with Oxygen, pp. 241, 394. Amsterdam: North Holland.Google Scholar
Angel, W.-L., Karplus, M., Poyart, C. & Burseaux, E. (1988). Analysis of proton release in oxygen binding by haemoglobin: implications for the cooperative mechanism. Biochemistry 27. 1285–1301.Google Scholar
Armstrong, W. H. & Lippard, S. J. (1984). Reversible protonation of the oxo bridge in a haemerythrin model compound. J. Am. Chem. Soc. 106, 4632–4633.Google Scholar
Armstrong, W. H., Spool, A., Papaefthymiou, G. C., Frankel, R. B. & Lippard, S. J. (1984). Assembly and characterisation of an accurate model for the diiron center in hemerythrin. J. Am. Chem. Soc. 106, 3653–3667.CrossRefGoogle Scholar
Arnone, A. (1972). X-ray diffraction study of binding of 2, 3-diphosphoglycerate to human deoxyhaemoglobin. Nature 237. 146–149.Google Scholar
Arrowsmith, C. H., Carey, J., Treat-Clemons, L. & Jardetzky, O. (1989). NMR assignments for the amino-terminal residues of trp repressor and their role in DNA binding. Biochemistry 28. 3875–3885.CrossRefGoogle ScholarPubMed
Baldwin, J. M. (1975). Structure and function of haemoglobin. Progr. Biophys. molec. Biol. 29, 225–320.CrossRefGoogle ScholarPubMed
Baldwin, J. M. & Chothia, C. (1979). Haemoglobin: the structural changes related to ligand binding and its allosteric mechanism. J. molec. Biol. 129, 183–191.Google Scholar
Barford, D. & Johnson, L. N. (1989). The allosteric transition of glycogen phosphorylase. Nature (in the Press).CrossRefGoogle Scholar
Bass, S., Sugiono, P., Arvidson, D. N., Gunsalus, R. P. & Youderian, P. (1987). RNA specificity determinants of E. coli tryptophan repressor binding. Genes & Development 1, 565–572.CrossRefGoogle Scholar
Bennett, W. S. & Steitz, T. A. (1978). Glucose-induced conformational change in yeast hexokinase. Proc. natn. Acad. Sci. U.S.A. 75, 4848–4852.Google Scholar
Berger, S. A. & Evans, P. R. (1989). Active site mutants altering the cooperativity of E. coli phosphofructokinase. (In preparation.)Google Scholar
Blackburn, M. N. & Schachman, H. K. (1977). Allosteric regulation of aspartate transcarbamylase. Effect of active site ligands on the reactivity of sulfydryl groups of the regulatory subunits. Biochemistry 16. 5084–5090.CrossRefGoogle Scholar
Blangy, D., Buc, H. & Monod, J. (1968). Kinetics of the allosteric interactions of phosphofructokinase from Escherichia coli. J. molec. Biol. 31, 13–35.CrossRefGoogle ScholarPubMed
Bloomer, A. C. & Butler, P. J. G. (1986). Tobacco mosaic virus: structure and assembly. In The Plant Viruses (ed. van Regenmortel, M. B. V. and Fraenkel-Conrat, H.). Plenum.Google Scholar
Bloomer, A. C., Champness, J. N., Bricogne, G., Staden, R. & Klug, A. (1978). Protein disk of tobacco mosaic virus at 2·8 Å resolution showing interactions within and between the subunits. Nature 276. 362–368.Google Scholar
Bolognesi, M., Cannillo, E., Ascenzi, P., Giacometti, G. M., Merli, A. & Brunori, M. (1982). Reactivity of ferric Aplysia and sperm whale myoglobins towards imidazole: X-ray and binding study. J. molec. Biol. 158, 305–315.Google Scholar
Bonaventura, C, Sullivan, B., Bonaventura, J. & Bourne, S. (1974). CO binding by hemocyanins of Limulus polyphemus, Busycon carica and Callinectes sapidus. Biochemistry 13. 4784–4789.CrossRefGoogle ScholarPubMed
Briehl, R. W. (1963). The relation between the oxygen equilibrium and aggregation of subunits in lamprey hemoglobin. J. biol. Chem. 238, 2361–2366.CrossRefGoogle Scholar
Brown, J. M., Powers, L., Kinkaid, B., Larrobee, J. A. & Spiro, T. G. (1980). Hemocyanin active site characterization and resonance Raman spectroscopy. J. Am. Chem. Soc. 102, 4210–4216.Google Scholar
Brunori, M., Kuiper, H. A. & Zolla, L. (1982). Ligand binding and stereochemical effects in hemocyanins. EMBO J. 1, 329–331.Google Scholar
Bunn, H. F. & Forget, G. B. (1985). Hemoglobin, Molecular and Clinical Aspects. Philadelphia: W. B. Saunders.Google Scholar
Butler, P. J. G. & Durham, A. C. H. (1977). Tobacco mosaic virus protein aggregation and the virus assembly. Adv. Prot. Chem. 31, 187–251.Google Scholar
Butler, P. J. G. & Klug, A. (1978). The assembly of a virus. Sci. Am. 239, 52–59.Google ScholarPubMed
Calhoun, D. B., Vanderkooi, J. M., Woodrow, G. V. III & Englander, S. W. (1983). Penetration of dioxygen into proteins studied by quenching of phosphorescence and fluorescence. Biochemistry 22. 1526–1532.Google Scholar
Carey, J. (1988). Gel retardation at low pH resolves trp repressor-DNA complexes for quantitative study. Proc. natn. Acad. Sci. U.S.A. 85, 975–979.Google Scholar
Carey, J. (1989). trp Repressor arms contribute binding energy without occupying unique locations on DNA. J. biol. Chem. 264, 1941–1945.Google Scholar
Carmichael, V. E., Dutton, P. J., Fyles, T. M., James, T. D., Swan, J. A. & Zojaji, M. (1989). Biomimetic ion transport: a functional model of a unimolecular ion channel. J. Am. Chem. Soc. III, 767–769.CrossRefGoogle Scholar
Caspar, D. (1963). Assembly and stability of the tobacco mosaic virus particle. Adv. Prot. Chem. 18, 37–121.Google Scholar
Cash, D. J. & Hess, G. P. (1980). Molecular mechanism of acetylcholine-controlled ion translocation across cell membranes. Proc. natn. Acad. Sci. U.S.A. 77, 842–846.CrossRefGoogle Scholar
Changeux, J. P. (1961). The feedback mechanism of biosynthetic L-threonine deaminase by L-isoleucine. Cold Spring Harb. Symp. quant. Biol. 26, 313–318.Google Scholar
Changeux, J. P., Gerhardt, J. C. & Schachman, H. K. (1968). Allosteric interaction in aspartate transcarbamylase. 1. Binding of specific ligands to the native enzyme and its isolated subunits. Biochemistry 7. 531–538.Google Scholar
Changeux, J. P., Giraudat, J. & Dennis, M. (1987). The nicotinic acid acetylcholine receptor: molecular architecture of a ligand-regulated ion channel. Trends pharmac. Sci. 8, 450–465.Google Scholar
Changeux, J. P. & Rubin, M. M. (1968). Allosteric interactions in aspartate transcarbamylase. III. Interpretation of experimental data in terms of the model of Monod, Wyman & Changeux. Biochemistry 7. 553–560.CrossRefGoogle Scholar
Cheng, X. & Schoenborn, (1989). Private communication.Google Scholar
Chothia, C. & Lesk, A. M. (1985). Helix movements in proteins. Trends in Biochem. Sci. 10, 116–118.CrossRefGoogle Scholar
Chu, A. H., Turner, B. W. & Ackers, G. K. (1984). Effects of protons on the oxygenlinked subassembly in human hemoglobin. Biochemistry 23. 604–617.Google Scholar
Cohen, G. & Jacob, F. (1959). Sur la répression de la synthèse des enzymes intervenants dans la formation du tryptophane chez Escherichia coli. C. r. hebd. séanc. Acad. Sci., Paris 248. 3490–3492.Google Scholar
Connelly, P. R., Gill, S. J., Miller, K. I., Zhou, G. & van Holde, K. E. (1989). Identical linkage and cooperativity of oxygen and carbon monoxide binding to Octopus dofleini hemocyanin. Biochemistry 28. 1835–1843.Google Scholar
Crick, F. H. C. & Orgel, L. E. (1964). The theory of interallelic complementation. J. molec. Biol. 8, 161–165.Google Scholar
Crothers, D. M. & Metzger, H. (1972). The influence of polyvalency on the binding properties of antibodies. Immunochemistry 9. 341–357.Google Scholar
Dalvit, C. & Wright, P. E. (1987). Assignment of resonances in the 1H nuclear magnetic resonance spectrum of the carbonmonoxide complex of sperm whale myoglobin by phase-sensitive two-dimensional techniques. J. molec. Biol. 194, 313–327.CrossRefGoogle Scholar
Derewenda, Z., Dodson, G., Emsley, P., Harris, D., Nagai, K., Perutz, M. F. & Renaud, J.-P. (1989). The stereochemistry of CO binding to normal human adult and Cowtown hemoglobins. J. molec. Biol. (in the Press).Google Scholar
Dickerson, R. E. & Geis, I. (1983). Haemoglobin: Structure, Function, Evolution, Pathology. Kenlo Park: Benjamin/Cummings.Google Scholar
Di Gabriele, A. D., Sanderson, M. R. & Steitz, T. A. (1989). Crystal lattice packing is important in determining the bend of a DNA dodecamer containing an adenine tract. Proc. natn. Acad. Sci. U.S.A. 86, 1816–1920.Google Scholar
Dohi, D., Sugita, Y. & Yoneyama, Y. (1973). The self-association and oxygen equilibrium of hemoglobin from the lamprey Entosphenus japonicus. J. biol. Chem. 248, 2354–2363.Google Scholar
Eisenberg, D., Almassy, R. J., Janson, C. A., Chapman, M. S., Shuh, S. W., Cascio, D. & Smith, W. W. (1987). Some evolutionary relationships of the primary biological catalysts glutamine synthetase and RuBisCo. Cold Spring Harb. Symp. quant. Biol 52. 483–490.Google Scholar
Eisenstein, E., Markby, D. W. & Schachman, H. K. (1989). Changes in stability and allosteric properties of aspartate transcarbamyolase resulting from amino acid substitutions in the zinc-binding domain of the regulatory chains. Proc. natn. Acad. Sci. U.S.A. 86, 3094–3098.CrossRefGoogle Scholar
Elam, W. T., Stern, E. A., McCallum, J. D. & Sanders-Loehr, J. (1983). An X-ray absorption study of the binuclear iron center in deoxyhemerythrin. J. Am. Chem. Soc. 105, 1919–1923.Google Scholar
Elber, R. & Karplus, M. (1989). Molecular dynamics simulations of myoglobin. (To be published.)Google Scholar
Ellerton, H. D., Ellerton, N. F. & Robinson, H. A. (1983). Hemocyanin – a current perspective. Progr. Biophys. Molec. Biol. 41, 143–248.Google Scholar
Englander, S. W. & Kallenbach, N. R. (1984). Hydrogen exchange and structural dynamics of proteins and nucleic acids. Q. Rev. Biophys. 16, 521–565.Google Scholar
Evans, D. R., Styliani, C. P.-L. & Lipscomb, W. N. (1975). Isolation and properties of a species produced by the partial dissociation of aspartate transcarbamylase from Escherichia coli. J. biol. Chem. 250 (10), 3571–3583.CrossRefGoogle ScholarPubMed
Evans, P. R. & Hudson, P. J. (1979). Structure and control of phosphofructokinase from Bacillus stearothermophilus. Nature 279. 500–504.Google Scholar
Evans, P. R., Farrants, G. W. & Lawrence, M. C. (1986). Crystallographic structure of allosterically inhibited phosphofructokinase at 7 Å resolution. J. molec. Biol. 191, 713–720.Google Scholar
Fermi, G. & Perutz, M. F. (1981). Atlas of Molecular Structures in Biology: Haemoglobin & Myoglobin. Oxford: Clarendon Press.Google Scholar
Fersht, A. R., Leatherbarrow, R. J. & Wells, T. N. C. (1986). Structure and activity of the tyrosyl-tRNA synthetase: the hydrogen bond in catalysis and specificity. Phil. Trans. R. Soc. Lond. A317, 305–320.Google Scholar
Fincham, J. R. S. & Day, P. R. (1963). Fungal Genetics. Oxford: Blackwell Scientific Publications.Google Scholar
Fletterick, R. J. & Madsen, N. B. (1980). The structures and related functions of phosphorylase a. A. Rev. Biochem. 49, 31–61.Google Scholar
Fletterick, R. J. & Sprang, S. R. (1982). Glycogen phosphorylase structures and function. Acc. Chem. Res. 15, 361–369.Google Scholar
Foote, J. & Schachman, H. K. (1985). Homotropic effects in aspartate transcarbamylase: What happens when the enzyme binds a single molecule of the bisubstrate analogue N-phosphonacetyl-L-aspartate? J. molec. Biol 186. 175–184.Google Scholar
Frederick, C. A., Grable, J., Melia, M., Samudzi, C, Jen-Jacobson, L., Wang, B. C., Greene, P., Boyer, H. W. & Rosenberg, J. M. (1984). Kinked DNA in crystalline complex with Eco RI endonuclease. Nature 309. 327–331.CrossRefGoogle Scholar
Frey, J. G., Eisenberg, D. & Eiserling, F. A. (1975). Glutamine synthetase forms three- and seven-stranded cables. Proc. natn. Acad. Sci. U.S.A. 72, 3402–3406.Google Scholar
Gaykema, W. P. J., Hol, W. G. J., Vereijken, J. M., Soeter, N. M., Bak, H. J. & Beintema, J. J. (1984). 3·2 Å structure of the copper-containing, oxygen-carrying protein Panulirus interruptus haemocyanin. Nature 309. 23–29.Google Scholar
Gelin, R. G., Lee, A. W.-M. & Karplus, M. (1983). Hemoglobin tertiary structural change on ligand binding. Its role in the cooperative mechanism. J. molec. Biol. 171, 480–559.CrossRefGoogle Scholar
Gerhardt, J. C. & Pardee, A. B. (1962). The enzymology of control by feedback inhibition. J. biol. Chem. 237, 891–896.Google Scholar
Gerhardt, J. C. & Schachman, H. K. (1968). Allosteric interactions in aspartate transcarbamylase II. Evidence for different conformational states of the protein in the presence and absence of specific ligands. Biochemistry 7. 538–552.Google Scholar
Gibbons, I., Ritchey, J. M. & Schachman, H. K. (1976). Concerted allosteric transitions in hybrids of aspartate transcarbamyìase containing different arrangements of active and inactive sites. Biochemistry 15. 1324–1330.CrossRefGoogle Scholar
Gibbons, I., Yang, Y. R. & Schachman, H. K. (1974). Cooperative interactions in aspartate transcarbamylase. I. Hybrids composed of native and chemically inactivated catalytic chains. Proc. natn. Acad. Sci. U.S.A. 71, 4452–4456.Google Scholar
Gill, S. J., Di Cera, E., Doyle, M. L. & Robert, C. H. (1988). New twists on an old story: hemoglobin. Trends biochem. Sci. 13, 465–467.CrossRefGoogle Scholar
Giraudat, J., Dennis, M., Heitmann, T., Haumont, P. T., Lederer, F. & Changeux, J. P. (1987). Structure of the high-affinity binding sites for non-competitive blockers of the acetylcholine receptor: [3H]chlorpromazine labels homologous residues in the β and δ chains. Biochemistry 26. 2410–2418.Google Scholar
Goldsmith, E., Sprang, S. & Fletterick, R. J. (1982). Structure of maltoheptaose by difference Fourier methods and a model for glycogen. J. molec. Biol. 156, 411–423.Google Scholar
Goldsmith, E. J., Sprang, S. R., Hamlin, R., Xuong, N. & Fletterick, R. J. (1989). Domain separation in the activation of glycogen phosphorylase a. (Submitted to Science.)Google Scholar
Gopalakrishnan, P. V. & Karush, F. (1974). Antibody affinity. VII. Multivalent interaction of anti-lactoside antibody. J. Immunol. 113, 769–778.Google Scholar
Gouaux, E. J. & Lipscomb, W. N. (1988). Three-dimensional structure of carbamoylphosphate and succinate bound to aspartate carbamoyltransferase. Proc. natn. Acad. Sci. U.S.A. 85, 4205–4208.Google Scholar
Graves, D. J. & Wang, J. H. (1972). α-glucan phosphorylases - chemical and physical basis of catalysis and regulation. In The Enzymes, (ed. Boyer, P. D.) vol. 7, PP. 435–482. New York: Academic Press.Google Scholar
Gunsalus, R. P., Gunsalus, M. A. & Gunsalus, G. L. (1986). Intracellular trp repressor levels in Escherichia coli. J. Bacteriol. 167, 272–278.Google Scholar
Hajdu, J., Acharya, K. R., Stuart, D. I., McLaughlin, P. J., Barford, D., Oikonomakos, N. G., Klein, H. & Johnson, L. N. (1987). Catalysis in the crystal: synchrotron radiation studies with glycogen phosphorylase b. EMBO J. 6, 539–545.Google Scholar
Heidmann, T., Beuchardt, J., Neumann, E. & Changeux, J. P. (1983). Rapid kinetics of agonist binding and permeability response analysed in parallel on acetylcholine receptor-rich membranes from Torpedo marmorata. Biochemistry 22. 5452–5459.Google Scholar
Heidner, E. J., Frey, T. G., Held, J., Weissman, L. J., Fenna, R. E., Lei, M., Harel, M., Kabsch, H., Sweet, R. M. & Eisenberg, D. (1978). New crystal forms of glutamine synthetase and implications for the molecular structure. J. molec. Biol. 122, 163–173.Google Scholar
Hellinga, H. W. & Evans, P. R. (1987). Mutations in the active site of Escherichia coli phosphofructokinase. Nature 327. 437–439.Google Scholar
Helmreich, E. J. M. & Klein, H. W. (1980). The role of pyridoxal phosphate in the catalysis of glycogen phosphorylase. Angew. Chem. Int. Ed. Eng. 19, 441–455.Google Scholar
Hendrickson, W. A. & Love, W. E. (1971). Structure of lamprey haemoglobin. Nature New Biol. 232, 197–203.Google Scholar
Hervè, J. (1989). Aspartate transcarbamylase from E. coli. In Allosteric Enzymes (ed. Hervé, G.) CRC Press (in the Press).Google Scholar
Hervé, G., Moody, M. F., Tave, P., Vachette, P. & Jones, P. T. (1985). Quaternary structure changes in aspartate transcarbamylase by X-ray scattering. J. molec. Biol. 185, 189–199.Google Scholar
Honzatko, R. B., Crawford, J. L., Monaco, H. L., Ladner, J. E., Edwards, B. F. P., Evans, D. R., Warren, S. G., Wiley, D. C., Ladner, R. C. & Lipscomb, W. N. (1982). Crystal and molecular structure of native and CTP-liganded aspartate carbamoyltransferase from Escherichia coli. J. molec. Biol. 160, 219–263.Google Scholar
Honzatko, R. B. & Lipscomb, W. N. (1982). Interactions of phosphate ligands with Escherichia coli aspartate carbamoyltransferase in the crystalline state. j. molec. Biol. 160, 265–286.Google Scholar
Howlett, G. J., Blackburn, M. N., Compton, J. G. & Schachman, H. K. (1977). Allosteric regulation of aspartate transcarbamylase. Analysis of the structural and functional behaviour in terms of a two-state model. Biochemistry 16. 5091–5099.Google Scholar
Howlett, G. J. & Schachman, H. K. (1977). Allosteric regulation of aspartate transcarbamylase. Changes in the sedimentation coefficient promoted by the bisubstrate analogue N-(phosphonacetyl)-L-aspartate. Biochemistry 16. 5077–5083.Google Scholar
Imai, K., (1982). Allosteric Effects in Haemoglobin. Cambridge University Press.Google Scholar
Jarvest, R. L., Lowe, G. & Potter, B. V. L. (1981). The stereochemical course of phosphoryl transfer catalyzed by Bacillus stearothermophilus and rabbit-muscle phosphofructokinase with a chiral [16O, 17O, 18O,]phosphate ester. Biochem.J. 199, 427–432.Google Scholar
Joachimiak, A. J., Kelley, R. L., Gunsalus, R. P., Yanofsky, C. & Sigler, P. B. (1983). Purification and characterization of the trp aporepressor. Proc. natn. Acad. Sci. U.S.A. 80, 668–672.Google Scholar
Johnson, B. A., Bonaventura, C. & Bonaventura, J. (1984). Allosteric modulation of Callinectes sapidus haemocyanin by lactate. Biochemistry 23. 872–878.Google Scholar
Johnson, K. A., Olson, J. S. & Phillips, G. N. Jr. (1989). The structure of myoglobinethyl isocyanide: histidine as a swinging door for ligand entry. J. molec. Biol. 207, 459–463.CrossRefGoogle ScholarPubMed
Johnson, L. N., Hajdu, J., Acharya, K. R., Stuart, D. I., McLaughlin, P. J., Oikonomakos, N. G. & Barford, D. (1989). Glycogen phosphorylase b. In Allosteric Proteins (ed. Hervé, G.), CRC Press.Google Scholar
Jullien, L. & Lehn, J.-M. (1988). The “Chundle” approach to molecular channels: synthesis of a macrocycle-based molecular bundle. Tetrahedron Lett. 29 (31), 3803–3806.Google Scholar
Kantrowitz, E. R. & Lipscomb, W. N. (1988). Escherichia coli aspartate transcarbamylase: the relations between structure and function. Science 241. 669–674.Google Scholar
Karush, F. (1978). The affinity of antibody: range, variability, and the role of multivalence. In Immunoglubulins (ed. Littman, G. W. and Good, R. A.), pp. 85–115. Plenum.Google Scholar
Ke, H.-M., Honzatko, R. B. & Lipscomb, W. N., (1984). Structure of unligated aspartate carbamoyltransferase of Escherichia coli at 2·6 Å resolution. Proc. natn. Acad. Sci. U.S.A. 81, 4037–4040.Google Scholar
Ke, H., Lipscomb, W. N., Cho, Y. & Honzatko, R. B. (1988). Complex of N-phosphonyl-L-aspartate with aspartate carbamoyltransferase. X-ray refinement, analysis of conformational changes and catalytic and allosteric mechanisms. J. molec. Biol. 204, 725–747.Google Scholar
Kelly, R. & Yanofsky, C. (1985). Mutational studies with the trp repressor of E. coli support the helix-turn-helix model of repressor recognition of operator DNA. Proc. natn. Acad. Sci. U.S.A. 82, 483–487.Google Scholar
Kilmartin, J. V. (1974). Influence of DPG on the Bohr effect of human haemoglobin. FEBS Lett. 38, 147–148.Google Scholar
Kilmartin, J. V., Breen, J. J., Roberts, G. C. K. & Ho, C. (1973). Direct measurement of the pK values of an alkaline Bohr group in human haemoglobin. Proc. natn. Acad. Sci. U.S.A. 70, 1246–1249.Google Scholar
Kim, K., Fettinger, J., Sessler, J. L., Cyr, M., Hugdahl, J., Collman, J. P. & Ibers, J. A. (1989). Structural characterisation of a sterically encumbered iron(II) porphyrin CO complex. J. Am. Chem. Soc. 111, 403–405.Google Scholar
Klug, A. & Rhodes, D. (1987). ‘Zinc fingers’: a novel protein motif for nucleic acid recognition. Trends biochem. Sci. 12, 464–469.Google Scholar
Knowles, J. (1980). Enzyme-catalyzed phosphoryl transfer reactions. An. Rev. Biochem. 49. 877–918.Google Scholar
Koshland, D. E. (1959). In The Enzymes, 2nd ed. vol. 1 (ed. Boyer, P. D.Lardy, H. & Myrbäck, K.), pp. 305–346. New York: Academic Press.Google Scholar
Koshland, D. E., Nemethy, G. & Filmer, D. (1966). Comparison of experimental binding data and theoretical models in proteins containing subunits. Biochemistry 5. 365–385.Google Scholar
Kotlarz, D. & Buc, H. (1982). Phosphofructokinases from Escherichia coli. Methods Enzymol. 90, 60–70.Google Scholar
Krause, K. L., Volz, K. W. & Lipscomb, W. N. (1987). 2·5 Å structure of aspartate carbamoyltransferase complexed with the bisubstrate analog N-(phosphonacetyl)-Laspartate. J. molec. Biol. 193, 527–553.Google Scholar
Krebs, E. G. (1986). The enzymology of control by phosphoryìation. In The Enzymes, 3rd ed. vol. 17 (ed. Boyer, P. D. and Krebs, E. G.), pp. 3–20. New York: Academic Press.Google Scholar
Krüse, J., Krüse, K. M., Witz, J., Chauvin, C, Jacrot, B. & Tardieu, A. (1982). Divalent ion-dependent reversible swelling of tomato bushy stunt virus and organisation of the expanded virion. J. molec. Biol. 162, 393–417.Google Scholar
Kuiper, H., Antonini, E. & Brunori, M. (1977). Kinetic control of cooperativity in the oxygen binding of Panulirus interruptus haemocyanin. J. molec. Biol. 116, 569–576.Google Scholar
Kuiper, H., Forlani, L., Chiancone, E., Antonini, E., Brunori, M. & Wyman, J. (1979). Multiple linkage in Panulirus interruptus. Biochemistry 18. 5849–5854.Google Scholar
Kuiper, H., Gaastra, W., Beintema, J. J., van Bruggen, E. F. J., Schepman, A. M. H. & Drenth, J. (1975). Subunit composition, X-ray diffraction, amino acid analysis and oxygen binding behaviour of Panulirus interruptus hemocyanin. J. molec. Biol. 99, 619–629.Google Scholar
Kuriyan, J., Wilz, S., Karplus, M. & Petsko, G. A. (1986). X-ray structure and refinement of carbonmonoxy (Fell)-myoglobin at 1·5 Å resolution. J. molec. Biol. 192, 133–154.Google Scholar
Ladjimi, M. M. & Kantrowitz, E. R. (1988). A possible model for the concerted transition in Escherichia coli aspartate transcarbamylase as deduced from site-directed mutagenesis studies. Biochemistry 27. 276–283.Google Scholar
Ladjimi, M. M., Middleton, S. A., Kellerher, K. S. & Kantrowitz, E. R. (1988). Relationship between domain closure and binding, catalysis and regulation in Escherichia coli aspartate transcarbamylase. Biochemistry 27. 268–276.Google Scholar
Lakowicz, J. R. & Weber, G. (1973). Quenching of protein fluorescence by oxygen. Detection of structural fluctuations in proteins on the nanosecond time scale. Biochemistry 12. 4171–4179.Google Scholar
Lalezari, I., Rahbar, S., Lalezari, P., Fermi, G. & Perutz, M. F. (1988). LR16, a compound with potent effects on the oxygen affinity of hemoglobin, on blood cholesterol, and on low density lipoprotein. Proc. natn. Acad. Sci. U.S.A. 85, 6117–6121.CrossRefGoogle ScholarPubMed
Lamy, J., Leclerc, M., Sizaret, P.-Y., Lamy, J., Miller, K. I., McParland, R. & van Holde, K. E. (1987). Octopus dofleini hemocyanin: structure of the seven-domain polypeptide chain. Biochemistry 26. 3509–3518.Google Scholar
Lau, F. T.-K. & Fersht, A. R. (1987). Conversion of allosteric inhibition to activation in phosphofructokinase by protein engineering. Nature 326. 811–812.Google Scholar
Lau, F. T.-K., Fersht, A. R., Hellinga, H. W. & Evans, P. R. (1987). Site-directed mutagenesis in the effector site of Escherichia coli phosphofructokinase. Biochemistry 26. 4143–4148.Google Scholar
Lawson, C. & Sigler, P. B. (1988). The structure of trp pseudorepressor at 1·65 Å shows why indol propionate acts as a trp ‘inducer’. Nature 333. 869–871.CrossRefGoogle ScholarPubMed
Lawson, C. L., Zhang, R.-G., Schevitz, R. W., Otwinowski, Z., Joachimiak, A. & Sigler, P. B. (1988). Flexibility of the DNA-binding domains of trp repressor. Proteins 3. 18–31.Google Scholar
Lear, J. D., Wasserman, Z. R. & DeGrade, W. F. (1988). Synthetic amphiphilic peptide models for protein ion channels. Science 240. 1177–1181.Google Scholar
Leonard, R. J., Labarca, C. G., Charnet, P., Davidson, N. & Lester, H. A. (1988). Evidence that the M2 spanning region lines the ion channel pore of the nicotinic receptor. Science 242. 1578–1581.Google Scholar
Liddington, R., Derewenda, Z., Dodson, G. & Harris, D. (1988). Structure of liganded T-state of haemoglobin identifies the origin of cooperative oxygen binding. Nature 331. 725–728.Google Scholar
Linzen, B., Soeter, N. M., Riggs, A. F., Schneider, H.-J., Schartau, W., Moore, M. D., Yokota, E., Behrens, P. Q., Nakashima, H., Takagi, T., Nemoto, T., Vereijken, J. M., Bak, H. J., Beintema, J. J., Volbeda, A., Gaykema, W. P. J. & Hol, W. G. J. (1985). The structure of arthropod haemocyanins. Science N. Y. 229, 519–524.Google Scholar
Louie, G., Tran, T., Englander, J. J. & Englander, S. W. (1988). Allosteric energy at the hemoglobin β-chain C-terminus studied by hydrogen exchange. J. molec. Biol. 201, 755–764.Google Scholar
McGeoch, D., McGeoch, J. & Morse, D. (1973). Synthesis of tryptophan operon RNA in a cell-free system. Nature New Biol. 245, 137–140.Google Scholar
McLaughlin, P. J., Stuart, D. I., Klein, H. W., Oinomakos, J. G. & Johnson, L. N. (1984). Substrate cofactor interactions for glycogen phosphorylase b: a binding study in the crystal with heptenitol and heptulose-2-phosphate. Biochemistry 23. 5862–5873.Google Scholar
Madsen, N. B. (1986). Glycogen phosphorylase. In The Enzymes, 3rd ed., vol. 17 (ed. Boyer, P. D. and Krebs, E. G.), pp. 366–394. New York: Academic Press.Google Scholar
Manwell, C. (1960). Oxygen equilibrium of the brachiopod Lingula hemerythrin. Science 132, 550–551.Google Scholar
Marmorstein, R. Q. & Sigler, P. B. (1988). Structure and mechanism of the trp repressor/operator system. In Nucleic Acids and Molecular Biology (ed. Eckstein, F.). Heidelberg. Springer-Verlag.Google Scholar
Marmorstein, R. Q., Joachimiak, A., Sprinzl, M. & Sigler, P. B. (1987). The structural basis for the interaction between L-tryptophan and the Escherichia coli trp aporepressor. J. biol. Chem. 262, 4922–4927.Google Scholar
Matsukawa, S., Itatani, Y., Mawatari, K., Shimokawa, Y. & Yoneyama, Y. (1978). Quantitative evaluation for the role β-146 His and β-143 His residues in the Bohr effect of human haemoglobin in the presence of 0·1 M chloride ion. J. biol. Chem. 259, 11479–11486.Google Scholar
Messana, C, Cerdonio, M., Shenkin, P., Noble, R. W., Fermi, G., Perutz, R. N. & Perutz, M. F. (1978). Influence of quaternary structure of the globin on thermal spin equilibria in different methaemoglobin derivatives. Biochemistry 17. 3652–3662.Google Scholar
Middleton, S. A. & Kantrowitz, E. R. (1988). Function of arginine-234 and aspartic acid-271 in domain closure, cooperativity, and catalysis in Escherichia coli aspartate transcarbamylase. Biochemistry 27, 8653–8660.Google Scholar
Miller, K. I. (1985). Oxygen equilibria of Octopus dofleini hemocyanin. Biochemistry 24. 4582–4586.Google Scholar
Momenteau, M., Scheidt, W. R., Elgenbrot, C. W. & Reed, C. A. (1988). A deoxymyoglobin model with a sterically unhindered axial imidazole. J. Am. Chem. Soc. 110, 1207–1215.Google Scholar
Monod, J., Changeux, J. P. & Jacob, F. (1963). Allosteric proteins and molecular control systems. J. molec. Biol. 6, 306–329.Google Scholar
Monod, J. & Cohen-Bazire, G. (1953). L'effet d'inhibition spécifique dans la biosynthése de la tryptophane-desmase chez Aerobacter aerogenus. C.r. hebd. séanc. Acad. Sci., Paris 236. 530–532.Google Scholar
Monod, J. & Jacob, F. (1961). Genetic regulation mechanisms in the synthesis of proteins. J. molec. Biol. 3, 318–356.Google Scholar
Monod, J., Wyman, J. & Changeux, J. P. (1965). On the nature of allosteric transitions: a plausible model. J. molec. Biol. 12, 88–118.CrossRefGoogle ScholarPubMed
Namba, K., Pattanayek, R. & Stubbs, G. (1989). Visualization of protein-nucleic acid interactions in a virus: refined structure of intact tobacco mosaic virus at 2·9 Å resolution by X-ray diffraction. J. molec. Biol. 208, 307–325.Google Scholar
Newell, J. O., Markby, D. W. & Schachman, H. K. (1989). Cooperative binding of the bisubstrate analog N-(phosphonacetyl)-L-aspartate to aspartate transcarbamylase and the heterotropic effects of ATP and CTP. J. biol. Chem. 264, 2476–2481.Google Scholar
Oiki, S., Danho, W., Madison, V. & Montal, M. (1988). M2 δ, a candidate for the structure lining the ionic channel of the nicotinic cholinergic receptor. Proc. natn. Acad. Sci. U.S.A. 85, 8703–8707.Google Scholar
Olson, J. S., Mathews, A. J., Rohlfs, R. J., Springer, B. A., Edelberg, K. D., Sliger, S. G., Tame, J., Renaud, J.-P, & Nagai, K. (1988). The role of the distal histidine in myoglobin and haemoglobin. Nature 336. 265–266.Google Scholar
Onan, K., Rebek, J., Costello, T. & Marshall, L. (1983). Allosteric effects: structural and thermodynamic origins and binding cooperativity in a subunit model. J. Am. Chem. Soc. 105, 6759–6760.Google Scholar
Otwinowski, Z., Schevitz, R. W., Zhang, R.-g., Lawson, C. L., Joachimiak, A., Marmorstein, R. Q., Luisi, B. & Sigler, P. B. (1988). The crystal structure of the trp repressor/operator complex at atomic resolution. Nature 335. 321–329.Google Scholar
Palm, D., Klein, H. W., Schinzel, R., Buehner, M. & Helmreich, E. J. M. (1989). The role of pyroxidal 5′-Phosphate in glycogen phosphorylase catalysis. Submitted to Perspectives in Biochem.Google Scholar
Perrella, M., Sabionedda, L., Samaja, M. & Rossi-Bernardi, L. (1986). The intermediate compounds between human hemoglobin and carbon monoxide at equilibrium and during approach to equilibrium. J. biol. Chem. 261, 8391–8396.Google Scholar
Perrella, M., Colosimo, A., Benazzi, L., Samaja, M. & Rossi-Bernardi, L. (1988). Intermediate compounds between hemoglobin and carbonmonoxide under equilibrium conditions.Symposion on Oxygen Binding and Heme Proteins, Asilomar Conference Grounds, Pacific Grove,California.Google Scholar
Perutz, M. F. & Mathews, F. S. (1966). An X-ray study of azide methaemoglobin. J. molec. Biol. 21, 199–202.Google Scholar
Perutz, M. F. (1970). Stereochemistry of cooperative effects in haemoglobin. Nature 228. 726–739.Google Scholar
Perutz, M. F. (1979). Regulation of oxygen affinity of hemoglobin: influence of structure of the globirt on the heme. A. Rev. Biochem. 48, 327–386.Google Scholar
Perutz, M. F. (1987). Molecular anatomy, physiology and pathology of hemoglobin. In The Molecular Basis of Blood Diseases (ed. Stamatoyannopoulos, G., Nienhuis, A. W., Leder, P. and Majerus, P. W.), pp. 127–178. Philadelphia: W. B. Saunders.Google Scholar
Perutuz, M. F. (1988). Allosteric enzymes: control by phosphorylation. Nature 336. 202–203.Google Scholar
Perutz, M. F., Fermi, G., Abraham, D. J., Poyart, C. & Bursaux, E. (1986). Hemoglobin as a receptor of drugs and peptides: X-ray studies of the stereochemistry of binding. J. Am. Chem. Soc. 108, 1064–1078.Google Scholar
Perutz, M. F., Fermi, G., Luisi, B., Shaanan, B. & Liddington, R. C. (1987). Stereochemistry of cooperative effects in hemoglobin. Accs. Chem. Res. 20, 309–321.Google Scholar
Perutz, M. F., Kilmartin, J. V., Nishikura, K., Fogg, J. H., Butler, P. J. G. & Rollema, H. S. (1980). Identification of residues contributing to the Bohr effect of human haemoglobin. J. molec. Biol 138. 649–670.Google Scholar
Perutz, M. F., Sanders, J. K. M., Chenery, D. H., Noble, R. W., Pennelly, R. R., Fung, L. W.-M., Ho, C, Giannini, I., Pörschke, D. & Winckler, H. (1978). Interactions between the quaternary structure of the globin and the spin state of the heme in ferric mixed spin derivatives of hemoglobin. Biochemistry 17. 3640–3652.Google Scholar
Phillips, S. E. V. & Schoenborn, B. P. (1981). Neutron diffraction reveals oxygenhistidine hydrogen bond in myoglobin. Nature 292. 81–82.Google Scholar
Phillips, S. E. V., Mansfield, I., Parsons, I., Davidson, B. E., Rafferty, J. B., Somers, W. S., Margarita, D., Cohen, G. N., St.-Girons, I. & Stockley, P. G. (1989). Tandem overlapping binding of the E. coli methionine repressor. Nature (in the Press).Google Scholar
Philo, S. & Dreyer, U. (1985). Quarternary structure has little influence on spin states in mixed-spin human methemoglobins. Biochemistry 24. 2985–2991.Google Scholar
Ptashne, M. (1986). A Genetic Switch. Cambridge Mass.: Cell Press; Oxford: Blackwell Scientific Publications.Google Scholar
Rafferty, J. B., Somers, W. S., St.-Girons, I. & Phillips, S. E. V. (1989). Threedimensional crystal structures of E. coli met repressor with and without co-repressors. Nature (in the Press).Google Scholar
Rebek, J., Wattley, R. V., Costello, T., Gadwood, R. & Marshall, L. (1981). Allosterische Effekte: Bindungskooperativität in einer Modellverbindung mit Untereinheiten. Angew. Chemie 93. 584–585.Google Scholar
Reem, R. C. & Solomon, E. I. (1987). Spectroscopic studies of the binuclear ferrous active site of deoxyhemerythrin; coordination number and probable bridging ligands for the native and ligand-bound forms. J. Am. Chem. Soc. 109, 1216–1226.Google Scholar
Remington, S., Wiegand, G. & Huber, R. (1982). Crystallographic refinement and atomic models of two different forms of citrate synthase at 2·7 Å and 1·7 Å resolution. J. molec. Biol. 158, 111–152.Google Scholar
Richardson, D. E., Reem, R. C. & Solomon, E. I. (1983). Cooperativity in oxygen binding to Lingula reevii hemerythrin: spectroscopic comparisons to the sipunculid hemerythrin binuclear active site. J. Am. Chem. Soc. 105, 7780–7781.Google Scholar
Ringe, D., Petsko, G. E., Kerr, D. E. & De Montellano, F. R. O. (1984). Reaction of myoglobin with phenylhydrazine – a molecular doorstop. Biochemistry 23. 2–4.Google Scholar
Robert, C. H., Decker, H., Richey, B., Gill, S. J. & Wyman, J. (1987). Nesting: hierarchies of allosteric interactions. Proc. natn. Acad. Set. U.S.A. 84, 1891–1895.Google Scholar
Robinson, I. K. & Harrison, S. C. (1982). Structure of the expanded state of tobacco bushy stunt virus. Nature 297. 563–568.Google Scholar
Rose, J. K., Squires, C. L., Yanofsky, C, Yang, H.-L. & Zubay, G. (1973). Regulation of in vitro transcription of the tryptophan operon by purified RNA polymerase in the presence of partially purified repressor and tryptophan. Nature New Biol. 245, 133–137.Google Scholar
Schachman, H. K. (1988). Can a simple model account for the allosteric transition of aspartate transcarbamylase? J. biol. Chem. 263, 18583–18586.Google Scholar
Scheidt, R. W. & Reed, C. A. (1981). Spin-state/stereochemical relationships in iron porphyrins: implications for the heme proteins. Chem. Rev. 81, 543–555.Google Scholar
Schevitz, R. W., Otwinowski, Z., Joachimiak, A., Lawson, C. L. & Sigler, P. B. (1985). The three-dimensional structure of trp repressor. Nature 317. 782–786.Google Scholar
Schirmer, T. & Evans, P. R. (1989). The crystal structure of the T-state of phosphofructokinase. (In preparation.)Google Scholar
Schleif, R. (1988). DNA binding to proteins. Science 241. 1182–1187.Google Scholar
Shaanan, B. (1983). Structure of human oxyhaemoglobin at 2·1 Å resolution. J. molec. Biol. 171, 31–50.Google Scholar
Shepherdson, M. & Pardee, A. B. (1960). Production and crystallization of aspartate transcarbamylase. J. biol. Chem. 235, 3233–3237.Google Scholar
Sheriff, S., Hendrickson, W. A. & Smith, J. L. (1987). Structure of myohemerythrin in the azidomet state at 1·7/1·3 Å resolution. J. molec. Biol. 197, 273–296.Google Scholar
Shiemke, A. K., Loehr, T. M. & Sanders-Loehr, J. (1984). Resonance Raman study of the μ-oxo bridged binuclear iron center in oxyhemerythrin. J. Am. Chem. Soc. 106, 4951–4956.Google Scholar
Shirakihara, Y. & Evans, P. R. (1988). Crystal structure of the complex of phosphofructokinase from Escherichia coli with its reaction products. J. molec. Biol. 204, 973–994.Google Scholar
Sprang, S. R., Acharya, K. R., Goldsmith, E. J., Stuart, D. I., Varvill, K., Fletterick, R. J., Madsen, N. B. & Johnson, L. N. (1988). Structural changes in glycogen phosphorylase induced by phosphorylation. Nature 336. 215–221.Google Scholar
Springer, B. A., Egeberg, K. D., Sugar, S. G., Rohlfs, R. J., Mathews, A. J. & Olson, J. S. (1989). Discrimination between oxygen and carbon monoxide and inhibition of autoxidation by myoglobin: site-directed mutagenesis of the distal histidine. J. biol. Chem. 264, 3057–3060.Google Scholar
Springer, B. A., Egeberg, K. D., Sugar, S. G., Rohlfs, R. J., Mathews, A. J. & Olson, J. S. (1989). Site-directed mutagenesis of sperm whale myoglobin: role of His E7 and Val E11 in ligand binding. J. biol. Chem. (In the press.)Google Scholar
Stadtman, E. R. & Ginsburg, A. (1974). The glutamine synthetase of Escherichia colt: structure and control. In The Enzymes, vol. 10, pp. 755–808. New York: Academic Press.Google Scholar
Stencamp, R. E., Sieker, L. C., Jensen, L. H., McCallum, J. D. & Sanders-Loehr, J. (1985). Active site structures of deoxyhemerythrin and oxyhemerythrin. Proc. natn. Acad. Sci. U.S.A. 82, 713–716.Google Scholar
Szabo, A. (1978). The kinetics of haemoglobin and transition state theory. Proc. natn. Acad. Sci. U.S.A. 75, 2108–2111.Google Scholar
Tauc, P., Vachette, P., Middleton, S. A. & Kantrowitz, E. R. (1989). Structural consequences of the replacement of Glu-239 by Gin in the catalytic chain of Escherichia coli aspartate transcarbamylase. Submitted to J. molec. Biol.Google Scholar
Toyoshima, C. & Unwin, N. (1988). Ion channel of acetylcholine receptor reconstructed from images of postsynaptic membranes. Nature 336. 247–250.Google Scholar
Trautmann, A. (1984). A comparative study of the activation of the cholinergic receptor by various agonists. Proc. R. Soc. Lond. 218, 241–251.Google Scholar
Umbarger, E. & Brown, B. (1958). Isoleucine and valine metabolism in Escherichia coli. VII. The negative feedback mechanism controlling isoleucine synthesis. J. biol. Chem. 233. 415–420.Google Scholar
Unwin, P. N. T. (1987). Design and action of cell communication channels. Chemica Scripta 27B, 47–51.Google Scholar
Unwin, P. N. T. & Ennis, P. D. (1984). Two configurations of a channel-forming membrane protein. Nature 307. 609–613.Google Scholar
Unwin, P. N. T., Toyoshima, C. & Kubalek, E. (1988). Arrangement of the acetylcholine receptor subunits in the resting and desensitized states, determined by cryoelectron microscopy of crystallized Torpedo postsynaptic membranes. J. Cell Biol. 107, 1123–1138.Google Scholar
Unwin, P. N. T. & Zampighi, G. (1980). Structure of the junction between communicating cells. Nature 283, 545.Google Scholar
Van Holde, K. E. & Miller, K. I. (1982). Haemocyanins. Q. Rev. Biophys. 15, 1–129.Google Scholar
Volbeda, A. & Hol, W. (1989 a). Pseudo-twofold symmetry in the copper-binding domain of arthropodan hemocyanins: possible implications for the evolution of oxygen transport proteins. J. molec. Biol. 206, 531–546.Google Scholar
Volbeda, A. & Hol, W. (1989 b). Crystal structure of hemocyanin from Panulirus interruptus refined at 3·2 Å resolution. J. molec. Biol. 208, in the press.Google Scholar
Watson, H. C. & Kendrew, J. C. (1961). Comparison between the amino-acid sequences of sperm whale myoglobin and of human haemoglobin. Nature 190. 670–672.Google Scholar
Weber, K. (1968). A new structural model of Escherichia coli aspartate transcarbamylase and the amino acid sequence of the regulatory chain. Nature 218. 1116–1119.Google Scholar
Wente, S. R. & Schachman, H. K. (1987). Shared active sites in oligomeric enzymes: model studies with defective mutants of aspartate transcarbamylase produced by sitedirected mutagenesis. Proc. natn. Acad. Sci. U.S.A. 84, 31–35.Google Scholar
Werner, W. E., Cann, J. R. & Schachman, H. K. (1989). Boundary spreading in sedimentation velocity experiments on partially liganded aspartate transcarbamylase. A ligand-mediated isomerization. J. molec. Biol. 206, 231–238.Google Scholar
Werner, W. E. & Schachman, H. K. (1989). Analysis of the ligand-promoted conformational change in aspartate transcarbamylase: evidence for a two-state transition from boundary spreading in sedimentation velocity experiments. J. molec. Biol. 206, 221–230.Google Scholar
Wiley, D. C. & Lipscomb, W. (1968). Crystallographic determination of the symmetry of aspartate transcarbamylase. Nature 218. 1119–1121.Google Scholar
Wyman, J. (1967). Allosteric linkage. J. Am. Chem. Soc. 89, 2202–2218.Google Scholar
Wyman, J. (1984). Linkage graphs: a study in the thermodynamics of macromolecules. Q. Rev. Biophys. 17, 453–488.Google Scholar
Yamashita, M. M., Almassy, R. J., Janson, C. A., Cascio, D. & Eisenberg, D. (1989). Refined atomic model of glutamine synthetase at 3·5 Å resolution. J. biol. Chem. (In the Press.)Google Scholar
Yates, R. A. & Pardee, A. B. (1956). Control of pyrimidine biosynthesis in Escherichia coli by a feedback mechanism. J. biol. Chem. 221, 757–770.Google Scholar
Zhang, K., Stern, E. A., Ellis, F., Sanders-Loehr, J. & Shiemke, A. K. (1988). The active site of hemerythrin as determined by X-ray Absorption Fine Structure. Biochemistry 27. 7470–7479.Google Scholar
Zhang, R.-g, Joachimiak, A., Lawson, C. L., Schevitz, R. W., Otwinowski, Z. & Sigler, P. B. (1987). The crystal structure of trp aporepressor at 1·8 Å shows how binding tryptophan enhances DNA affinity. Nature 327. 591–597.Google Scholar
Zubay, G., Morse, D. E., Schrenk, W. J. & Miller, J. H. M. (1972). Detection and isolation of the repressor protein for the tryptophan operator of Escherichia coli. Proc. natn. Acad. Sci. U.S.A. 69, 1100–1103.Google Scholar