Structural highlights
Function
[GAG_RSVP] Capsid protein p27 forms the spherical core of the virus that encapsulates the genomic RNA-nucleocapsid complex (By similarity). The aspartyl protease mediates proteolytic cleavages of Gag and Gag-Pol polyproteins during or shortly after the release of the virion from the plasma membrane. Cleavages take place as an ordered, step-wise cascade to yield mature proteins. This process is called maturation. Displays maximal activity during the budding process just prior to particle release from the cell (By similarity).
Publication Abstract from PubMed
Inositol hexakisphosphate (IP6) is an assembly cofactor for HIV-1. We report here that IP6 is also used for assembly of Rous sarcoma virus (RSV), a retrovirus from a different genus. IP6 is ~100-fold more potent at promoting RSV mature capsid protein (CA) assembly than observed for HIV-1 and removal of IP6 in cells reduces infectivity by 100-fold. Here, visualized by cryo-electron tomography and subtomogram averaging, mature capsid-like particles show an IP6-like density in the CA hexamer, coordinated by rings of six lysines and six arginines. Phosphate and IP6 have opposing effects on CA in vitro assembly, inducing formation of T = 1 icosahedrons and tubes, respectively, implying that phosphate promotes pentamer and IP6 hexamer formation. Subtomogram averaging and classification optimized for analysis of pleomorphic retrovirus particles reveal that the heterogeneity of mature RSV CA polyhedrons results from an unexpected, intrinsic CA hexamer flexibility. In contrast, the CA pentamer forms rigid units organizing the local architecture. These different features of hexamers and pentamers determine the structural mechanism to form CA polyhedrons of variable shape in mature RSV particles.
Structure of the mature Rous sarcoma virus lattice reveals a role for IP6 in the formation of the capsid hexamer.,Obr M, Ricana CL, Nikulin N, Feathers JR, Klanschnig M, Thader A, Johnson MC, Vogt VM, Schur FKM, Dick RA Nat Commun. 2021 May 28;12(1):3226. doi: 10.1038/s41467-021-23506-0. PMID:34050170[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Obr M, Ricana CL, Nikulin N, Feathers JR, Klanschnig M, Thader A, Johnson MC, Vogt VM, Schur FKM, Dick RA. Structure of the mature Rous sarcoma virus lattice reveals a role for IP6 in the formation of the capsid hexamer. Nat Commun. 2021 May 28;12(1):3226. doi: 10.1038/s41467-021-23506-0. PMID:34050170 doi:http://dx.doi.org/10.1038/s41467-021-23506-0
