6sa9
From Proteopedia
Endogenous Retrovirus HML2 Capsid NTD
Structural highlights
FunctionPOK9_HUMAN The products of the Gag polyproteins of infectious retroviruses perform highly complex orchestrated tasks during the assembly, budding, maturation, and infection stages of the viral replication cycle. During viral assembly, the proteins form membrane associations and self-associations that ultimately result in budding of an immature virion from the infected cell. Gag precursors also function during viral assembly to selectively bind and package two plus strands of genomic RNA. Endogenous Gag proteins may have kept, lost or modified their original function during evolution (By similarity). Early post-infection, the reverse transcriptase converts the viral RNA genome into double-stranded viral DNA. The RNase H domain of the reverse transcriptase performs two functions. It degrades the RNA template and specifically removes the RNA primer from the RNA/DNA hybrid. Following nuclear import, the integrase catalyzes the insertion of the linear, double-stranded viral DNA into the host cell chromosome. Endogenous Pol proteins may have kept, lost or modified their original function during evolution (By similarity). Publication Abstract from PubMedThe HML2 (HERV-K) group constitutes the most recently acquired family of human endogenous retroviruses, with many proviruses less than one million years old. Many maintain intact open reading frames and provirus expression together with HML2 particle formation are observed in early stage human embryo development and are associated with pluripotency as well as inflammatory disease, cancers and HIV-1 infection. Here, we reconstruct the core structural protein (CA) of an HML2 retrovirus, assemble particles in vitro and employ single particle cryogenic electron microscopy (cryo-EM) to determine structures of four classes of CA Fullerene shell assemblies. These icosahedral and capsular assemblies reveal at high-resolution the molecular interactions that allow CA to form both pentamers and hexamers and show how invariant pentamers and structurally plastic hexamers associate to form the unique polyhedral structures found in retroviral cores. Structural basis for Fullerene geometry in a human endogenous retrovirus capsid.,Acton O, Grant T, Nicastro G, Ball NJ, Goldstone DC, Robertson LE, Sader K, Nans A, Ramos A, Stoye JP, Taylor IA, Rosenthal PB Nat Commun. 2019 Dec 20;10(1):5822. doi: 10.1038/s41467-019-13786-y. PMID:31862888[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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