Month: September 2022

MUTANT PARTICLES. "Viral morphogenesis sometimes yields aberrant, off-pathway products. These non-infectious particles commonly arise from mutations in genes encoding structural proteins (e.g., an amber mutation in scaffolding protein or point mutations in coat protein)." http://www.sciencedirect.com/science/article/pii/S0042682215001920 View in LinkedIn

MUTATION MALWARE. "In the absence of scaffolding protein, P22 coat protein will form empty, aberrant assemblies, consisting of both hexons and pentons, such as T=4 and T=7 icosahedral capsids, or spiral structures. Similarly, mutations resulting in amino acid substitutions in coat protein that affect its flexibility or structure can influence the morphology of resulting products." http://www.sciencedirect.com/science/article/pii/S0042682215001920 View in LinkedIn

MUTATION CONSEQUENCES. "As seen with spiral polymers, scaffolding protein is important to direct threefold interactions. Interaction with scaffolding protein thus affects the geometry and imposes the correct radius of curvature, resulting in assembly of proper products with exquisite fidelity." https://lnkd.in/dXvJFtt View in LinkedIn

BASIC TEMPLATE. "The HK97-fold, despite sequence, structural, and functional divergences, is a basic template for formation of a proteinacious shell utilized by viruses and prokaryotic cells alike. The protein shell, composed of HK97-like subunits, serves a protective role for the genomes of viruses infecting all three domains of life. Prokaryotic cells also utilize the HK97-fold to form encapsulin nanocompartments, and possibly gene transfer agent particles that contribute to high frequencies of horizontal gene transfer." http://www.sciencedirect.com/science/article/pii/S0042682215001920 View in LinkedIn

SIZE AND FUNCTION OF CAPSID. "The capsid size has likely evolved to accommodate the size of the material to be packaged as T. maritima encapsulins package small ferritin-like proteins inside a particle with an inner volume of 4.18×10(6) Å3 while Phage G requires a much larger capsid (inner volume=1.87×10(9) Å3) to package its 670 kb chromosome." https://lnkd.in/dXvJFtt View in LinkedIn

EMBELLISHMENTS ADD FUNCTIONALITY. "In addition to varied sizes, an amazing diversity of loop and domain embellishments to the basic HK97-fold increase its functionality and often provide alternate ways to stabilize the assembled particles. Particles containing subunits with the HK97-fold will undoubtedly continue to be discovered with other variations for accomplishing folding, assembly, and capsid stabilization." http://www.sciencedirect.com/science/article/pii/S0042682215001920 View in LinkedIn

OUTLIER. "Presently, HK97 is the only known virus to display covalent chainmail formed with isopeptide crosslinks and thus constitutes its own group. The use of a single protein in HK97 to form a stable structure represents a highly optimized strategy, perhaps resulting from evolutionary selection. As such, it may represent a more recent emergence of complexes with the HK97-like fold." https://lnkd.in/dQSWuND View in LinkedIn

MORE KINGDOMS USING TEMPLATES. "Viruses likely originated from ancient cells through encapsulating cellular plasmids or genome fragments by cellular protein. Indeed, cellular complexes resembling the structure and topology of HK97 gp5 have been found in both bacteria and archaea cells. Similarly, it is natural to expect that cellular proteins with the BPP-1 topology of the HK97-like fold also exist elsewhere." http://www.aimspress.com/article/10.3934/biophy.2015.2.200/fulltext.html View in LinkedIn

GENE EVOLUTION. "The gene encoding one of these topologies might have evolved from the other through non-circular permutation in ancient cells through horizontal gene transfer—a rule for evolution in the prokaryotic world. In fact, although rare, non-circular permutation has been observed in cells, as exemplified by bacterial DNA methyltransferases." https://lnkd.in/dQSWuND View in LinkedIn

OTHER SPAWN. "These ancient cellular genes, encoding cellular proteins with the HK97-like fold, might have independently given rise to the viral proteins with different topologies and insertional domains. Adaptation to more complex environments of higher level organisms such as animal cells could have naturally led to acquisition of additional structures by way of insertions at locations of the loops of the HK97-like fold, as revealed in eukaryotic viruses such as herpesviruses. Such insertional domains could also give rise to auxiliary proteins by way of gene splicing such as the proposed case between BPP-1 and P22-like phages." http://www.aimspress.com/article/10.3934/biophy.2015.2.200/fulltext.html View in LinkedIn