Disulfide Linkage and Structure of Highly Stable Yeast-derived Virus-like Particles of Murine Polyomavirus

Abstract

Background: Polyoma virus-like particles produced in vivo (yVLPs) are more stable than those assembled in vitro. Results: yVLPs exhibit higher disulfide connectivity and additional N-terminal structural features in VP1. Conclusion: An ordered network of cystine-bridged VP1 N-terminal peptides contributes to polyoma virus capsid stability. Significance: These results suggest a role for intracellular components in optimizing capsid assembly.

Genome Sequence of a Fish-Associated Polyomavirus, Black Sea Bass (Centropristis striata) Polyomavirus 1

“…Analysis of potential splicing signals suggests that the virus may express an unusual N-extended form of VP1 from a spliced mRNA. The hypothetical first exon of VP1 encodes a cysteine-rich leader analogous to flexible N-terminal motifs that are known to form stabilizing disulfide bonds in the virions of other polyomavirus species ( 9 ).…”

Assembly and Purification of Polyomavirus-Like Particles from Plants

“…On the other hand, the DVP1 modification resulted in monodisperse VLPs of a slightly larger radius than wtVLPs, more similar to native virions [37]. The N-terminal arm of VP1 forms a clamp to hold C-terminal protrusions from neighbouring capsomeres in place [44], and recent structural evidence suggests the presence of intercapsomeric disulphide bridges linking the N-termini of VP1 from different capsomeres [43]. Flexibility in this clamping mechanism allows capsomeres to exist in both pentavalent and hexavalent states [31,37] as well as tolerating the assembly of polymorphic particles in the polyomaviruses [28,38].…”

“…Dimers and higher order VP1 aggregates have been seen on reducing SDS-PAGE gels from purified virions [13] and recombinant VP1 expressed in insect cells [15]. It is expected that both intracapsomeric and intercapsomeric disulphide bridges are more efficiently formed during in vivo assembly than in vitro and this results in VLPs from eukaryotic cells possessing greater stability than in vitro-assembled VLPs [43]. Despite limited optimisation performed during this study and the analysis of just two gradient fractions, the recovery of purified VLPs approaches the highest reported levels of HPV L1 protein in crude extracts of plant tissue [21,23].…”

Virus-like particles as vaccine.

“…2A). Stability of the dodecameric structure does not depend on disulfide bridges or cations as in other VLPs (Simon et al, 2014). Instead, the major mechanism of stability lies in interlocking of the 60 N-terminal domains derived from 12 pentameric penton bases, which results in formation of a strong net stabilizing the VLP (Szolajska et al, 2012).…”