Boulard, Y. | Search bioRxiv

bioRxiv2024

Studying self-assembly of norovirus capsid by a combination of in silico methods

Understanding how macromolecular assembly occurs is a fundamental and challenging problem because spontaneous, precise assembly is at the center of most biological processes. It is an elaborate process that requires non-covalent stable interactions between partners to stabilize the desired architecture for a specific purpose. One of the advantages of virus models is that under adequate conditions capsid proteins can be efficiently assembled in vitro in the absence of any other component, providing simplified experimental models that can be rigorously characterized. The present study aims at describing the initial steps of molecular self-assembly of norovirus-like particles (NoVLPs, composed solely of the major norovirus capsid protein VP1), by combining in silico computational approaches to explore complementary physical properties. We show that this strategy allows not only recapitulating but also revising a former NoVLP assembly model. Our approach can be applied and extended to other problems in macromolecular assembly.

bioinformatics↗

bioRxiv2023

The smallest infectious substructure encoding the prion strain structural determinant revealed by spontaneous dissociation of misfolded prion protein assemblies

It is commonly accepted that the prion replicative propensity and strain structural determinant (SSD) are encoded in the fold of PrPSc amyloid fibril assemblies. By exploring the quaternary structure dynamicity of several prion strains, we revealed that all mammalian prion assemblies exhibit the generic property of spontaneously generating two sets of discreet infectious tetrameric and dimeric species differing significantly by their specific infectivity. By using perturbation approaches such as dilution and ionic strength variation, we demonstrated that these two oligomeric species were highly dynamic and evolved differently in the presence of chaotropic agents. In general, our observations of seven different prion strains from three distinct species highlight the high dynamicity of PrPSc assemblies as a common and intrinsic property of mammalian prions. The existence of such small infectious PrPSc species harboring the SSD indicates that the prion infectivity and the SSD are not restricted only to the amyloid fold but can also be encoded in other alternative quaternary structures. Such diversity in the quaternary structure of prion assemblies tends to indicate that the structure of PrPSc can be divided into two independent folding domains: a domain encoding the strain structural determinant and a second domain whose fold determines the type of quaternary structure that could adopt PrPSc assemblies. HighlightsO_LIMammalian prion assemblies are highly dynamic C_LIO_LIPrion assemblies spontaneously disassemble into two infectious oligomers C_LIO_LIPrion infectivity is not exclusively encoded in the amyloid fibrils structure C_LIO_LITwo independent folding domains could structure Prion assemblies C_LI

biochemistry↗