This study presents the background, rationale and method of action of Biovacc-19, a candidate vaccine for corona virus disease 2019 (Covid-19), now in advanced preclinical development, which has already passed the first acute toxicity testing. Unlike conventionally developed vaccines, Biovacc-19’s method of operation is upon nonhuman-like (NHL) epitopes in 21.6% of the composition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)’s spike protein, which displays distinct distributed charge including the presence of a charged furin-like cleavage site. The logic of the design of the vaccine is explained, which starts with empirical analysis of the aetiology of SARS-CoV-2. Mistaken assumptions about SARS-CoV-2’s aetiology risk creating ineffective or actively harmful vaccines, including the risk of antibody-dependent enhancement. Such problems in vaccine design are illustrated from past experience in the human immunodeficiency viruses domain. We propose that the dual effect general method of action of this chimeric virus’s spike, including receptor binding domain, includes membrane components other than the angiotensin-converting enzyme 2 receptor, which explains clinical evidence of its infectivity and pathogenicity. We show the nonreceptor dependent phagocytic general method of action to be specifically related to cumulative charge from insertions placed on the SARS-CoV-2 spike surface in positions to bind efficiently by salt bridge formations; and from blasting the spike we display the NHL epitopes from which Biovacc-19 has been down-selected.

Downy brome is a grassy weed that infests millions of acres of winter wheat in the Western United States and costs farmers millions of dollars in lost yields. It can not be controlled consistently using chemicals or cultural practices. Isolates of naturally occurring rhizobacteria have shown potential as biological control agents for downy brome. Centrifuged supernatant from aerobic shake cultures of Pseudomonas fluorescens strain D7 suppressed germination of seeds and reduced root and shoot growth of downy brome in agar diffusion assays. The present article relates to the isolation and characterization of active compounds from strain D7. The active compounds were denatured and lost activity with commonly used techniques of extraction, concentration, and purification of microbial products. Two unusual techniques for isolation and partial purification of the active compounds from supernatant of strain D7 were developed. With one technique, supernatant was concentrated at 30 to 35 C under vacuum to 10% of the initial volume. Subsequently, the concentrate was chromatographed on sephadex gels to separate the active fraction. With the second technique, cell-free supernatant was frozen, with or without prior concentration, at −12 C for 12 to 24 h. The frozen supernatant was then thawed at 2 to 4 C, resulting in precipitation and crystallization of the active fraction. The active fraction isolated with either method inhibited downy brome. Inhibition was complete at concentrations as low as 1 mg total dry matter L-1 agar. Also, the active fraction inhibited the plant pathogenic fungus Gaeumannomyces graminis var. tritici. Chemical analysis of the active fraction complex revealed the presence of chromopeptides and other peptides, fatty acid esters, and a lipopolysaccharide matrix. Separation of any of the components from the complex resulted in nearly complete loss of activity against downy brome.

Jelly coat of starfish eggs has the capacity to activate homologous spermatozoa and induce the acrosome reaction. We have isolated 12 sperm-activating peptides (SAPs) from the egg jelly of the starfish, Asterias amurensis. Eleven SAPs were structurally identified by sequence analysis and electro-spray ionisation mass spectrometry. All of them are glutamine-rich tetratriacontapeptides with an intramolecular disulphide linkage between Cys8 and Cys32. They are much larger than sea urchin SAPs and do not show any significant sequence similarities to known proteins. Thus we have collectively named them asterosaps. The amino terminal region, where structural diversity of asterosaps is observed, is not important for their activity, whereas the disulphide linkage is essential. Asterosaps do not induce the acrosome reaction by themselves, but are able to induce the acrosome reaction in combination with an egg jelly glycoconjugate named ARIS. Furthermore, anti-asterosap rabbit antibody significantly decreased the acrosome reaction-inducing activity of the jelly solution and the activity was restored by addition of excess asterosap. These results support our hypothesis that the main physiological role of SAPs is the induction of the acrosome reaction in cooperation with two other jelly components, ARIS and Co-ARIS.

Two angiotensin converting enzyme (ACE)-inhibitory peptides were isolated from enzyme modified cheese (EMC) and their amino acid sequences were identified as Leu-Gln-Pro and Met-Ala-Pro. The EMC was prepared by a combination of Protease N, Umamizyme, and Flavourzyme 500L. Both peptides were derived from β-casein, f 88-90 and f 102-104, respectively. Met-Ala-Pro showed strong ACE inhibitory activity (IC50=0·8 μm) and antihypertensive activity in spontaneously hypertensive rats (SHR) after single oral administration. The IC50 value of Met-Ala-Pro was not affected by pre-incubation with ACE, suggesting that this peptide was a true ACE-inhibitory peptide. We report here, for the first time antihypertensive peptides from EMC.

Dental remineralization may be achieved by mediating the interactions between tooth surfaces with free ions and biomimetic peptides. We recently developed octuplet repeats of aspartate-serine-serine (DSS-8) peptide, which occurs in high abundance in naturally occurring proteins that are critical for tooth remineralization. In this paper, we evaluated the possible role of DSS-8 in enamel remineralization. Human enamel specimens were demineralized, exposed briefly to DSS-8 solution, and then exposed to concentrated ionic solutions that favor remineralization. Enamel nano-mechanical behaviors, hardness and elastic modulus, at various stages of treatment were determined by nanoindentation. The phase, microstructure and morphology of the resultant surfaces were characterized using the grazing incidence X-ray diffraction (GIXD), variable pressure scanning electron microscopy (VPSEM), and atomic force microscopy (AFM), respectively. Nanoindentation results show that the DSS-8 remineralization effectively improves the mechanical and elastic properties for demineralized enamel.

The Human Genome Project continues to reveal the genetic basis for numerous acquired and inherited diseases ranging from cancer, HIV, and heart disease to muscular dystrophy and hemophilia. With this wealth of information, the ability to design patient-specific drugs that alter the cellular machinery at the genetic level in a way that controls or treats a specific disease will increasingly become a reality. Designing nucleic acid drugs as well as engineering novel delivery vehicles that encapsulate and effectively transport genetic materials into cells provides an opportunity to enhance the understanding of disease mechanisms and may help treat or cure these diseases. This issue of MRS Bulletin on “Designer Materials for Nucleic Acid Delivery” explores the diverse materials—polymers, lipids, nanoparticles, biocompatible scaffolds, and engineered peptides—that are being evaluated for the intracellular delivery of nucleic acids. These synthetic delivery systems are actively being investigated for many research purposes that range from gene-based therapy, genetic vaccine, and RNA interference to gene function and cellular signaling studies. This area is currently being pursued by a broad group of academic, clinical, and industrial researchers at both the fundamental and applied level, motivated by the widespread implications for human health. In this introductory article, we provide a general tutorial to gene-based therapies and a brief overview of the many areas of materials research that are currently making a tremendous impact on this interdisciplinary field.We conclude with a discussion of the future challenges that materials researchers face in developing viable nucleic acid delivery vehicles.

Traditional anti-cancer drugs preferentially kill rapidly growing tumour cells rather than normal cells. However, most of these drugs have no preferential selection towards cancer cells and are taken up by the whole body, resulting in significant adverse side effects. Therapeutic molecules that could specifically inhibit undesirable phenotypes are an attractive way of eliminating cancer cells. There is a widespread effort to develop inhibitors against signal transduction molecules that play a key role in the proliferative, migratory and invasive properties of a cancer cell. Grb7 is an adaptor-type signalling protein that is recruited via its Src-homology 2 (SH2) domain to a variety of tyrosine kinases. Grb7 is overexpressed in breast, oesophageal and gastric cancers, and may contribute to the invasive potential of cancer cells. Molecular interactions involving Grb7 therefore provide attractive targets for therapeutic intervention.

The formation of the N-terminal β-hairpin of ubiquitin is thought to be an early event in the folding of this small protein. Previously, we have shown that a peptide corresponding to residues 1–17 of ubiquitin folds autonomously and is likely to have a native-like hairpin register. To investigate the causes of the stability of this fold, we have made mutations in the amino acids at the apex of the turn. We find that in a peptide where Thr9 is replaced by Asp, U(1–17)T9D, the native conformation is stabilized with respect to the wild-type sequence, so much so that we are able to characterize the structure of the mutant peptide fully by NMR spectroscopy. The data indicate that U(1–17)T9D peptide does indeed form a hairpin with a native-like register and a type I turn with a G1 β-bulge, as in the full-length protein. The reason for the greater stability of the U(1–17)T9D mutant remains uncertain, but there are nuclear Overhauser effects between the side chains of Asp9 and Lys11, which may indicate that a charge–charge interaction between these residues is responsible.

Peptide GFSKAELAKARAAKRGGY folds in an α-helical conformation that is stabilized by formation of a hydrophobic staple motif and an N-terminal capping box (Munoz V, Blanco FJ, Serrano L, 1995, Struct Biol 2:380–385). To investigate backbone and side-chain internal motions within the helix and hydrophobic staple, residues F2, A5, L7, A8, and A10 were selectively 13C- and 15N-enriched and NMR relaxation experiments were performed in water and in water/trifluoroethanol (TFE) solution at four Larmor frequencies (62.5, 125, 150, and 200 MHz for 13C). Relaxation data were analyzed using the model free approach and an anisotropic diffusion model. In water, angular variances of motional vectors range from 10 to 20° and backbone φ,ψ bond rotations for helix residues A5, L7, A8, and A10 are correlated indicating the presence of Cα-H, Cα-Cβ, and N-H rocking-type motions along the helix dipole axis. L7 side-chain CβH2 and CγH motions are also correlated and as motionally restricted as backbone CαH, suggesting considerable steric hindrance with neighboring groups. In TFE which stabilizes the fold, internal motional amplitudes are attenuated and rotational correlations are increased. For the side chain of hydrophobic staple residue F2, wobbling-in-a-cone type motions dominate in water, whereas in TFE, the Cβ-Cγ bond and phenyl ring fluctuate more simply about the Cα-Cβ bond. These data support the Daragan–Mayo model of correlated bond rotations (Daragan VA, Mayo KH, 1996, J Phys Chem 100:8378–8388) and contribute to a general understanding of internal motions in peptides and proteins.

The folding kinetics of human common-type acylphosphatase (cAcP) from its urea- and TFE-denatured states have been determined by stopped-flow fluorescence techniques. The refolding reaction from the highly unfolded state formed in urea is characterized by double exponential behavior that includes a slow phase associated with isomerism of the Gly53–Pro54 peptide bond. However, this slow phase is absent when refolding is initiated by dilution of the highly α-helical denatured state formed in the presence of 40% trifluoroethanol (TFE). NMR studies of a peptide fragment corresponding to residues Gly53–Gly69 of cAcP indicate that only the native-like trans isomer of the Gly–Pro peptide bond is significantly populated in the presence of TFE, whereas both the cis and trans isomers are found in an ∼1:9 ratio for the peptide bond in aqueous solution. Molecular modeling studies in conjunction with NMR experiments suggest that the trans isomer of the Gly53–Pro54 peptide bond is stabilized in TFE by the formation of a nonnative-like hydrogen bond between the CO group of Gly53 and the NH group of Lys57. These results therefore reveal that a specific nonnative interaction in the denatured state can increase significantly the overall efficiency of refolding.