5a32
From Proteopedia
Revision as of 08:20, 26 June 2019
Electron cryo-microscopy of Cowpea Mosaic Virus containing RNA-1 (CPMVb)
Structural highlights
Function[POL2_CPMVS] Movement protein: transports viral genome to neighboring plant cells directly through plasmosdesmata, without any budding. The movement protein allows efficient cell to cell propagation, by bypassing the host cell wall barrier. Acts by forming a tubular structure at the host plasmodesmata, enlarging it enough to allow free passage of virion capsids. Binds to GTP and to single-stranded RNA and single-stranded DNA in a non-sequence-specific manner.[1] [2] [3] [4] The cleavable C-terminus of small coat protein seems to be involved in the packaging of the virion RNAs. Also seems to act as suppressor of post-transcriptional gene silencing (PTGS), a mechanism of plant viral defense that limits the accumulation of viral RNAs.[5] [6] [7] [8] Publication Abstract from PubMedCowpea mosaic virus is a plant-infecting member of the Picornavirales and is of major interest in the development of biotechnology applications. Despite the availability of >100 crystal structures of Picornavirales capsids, relatively little is known about the mechanisms of capsid assembly and genome encapsidation. Here we have determined cryo-electron microscopy reconstructions for the wild-type virus and an empty virus-like particle, to 3.4 A and 3.0 A resolution, respectively, and built de novo atomic models of their capsids. These new structures reveal the C-terminal region of the small coat protein subunit, which is essential for virus assembly and which was missing from previously determined crystal structures, as well as residues that bind to the viral genome. These observations allow us to develop a new model for genome encapsidation and capsid assembly. Mechanisms of assembly and genome packaging in an RNA virus revealed by high-resolution cryo-EM.,Hesketh EL, Meshcheriakova Y, Dent KC, Saxena P, Thompson RF, Cockburn JJ, Lomonossoff GP, Ranson NA Nat Commun. 2015 Dec 10;6:10113. doi: 10.1038/ncomms10113. PMID:26657148[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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