6cj6
Structure of the poxvirus protein F9
Structural highlights
FunctionPG053_VACCW Component of the entry fusion complex (EFC), which consists of 11 proteins. During cell infection, this complex mediates entry of the virion core into the host cytoplasm by a two-step mechanism consisting of lipid mixing of the viral and cellular membranes and subsequent pore formation.[1] [2] Publication Abstract from PubMedThe poxvirus F9 protein is a component of the vaccinia virus entry fusion complex (EFC) which consists of 11 proteins. The EFC forms a unique apparatus among viral fusion proteins and complexes. We solved the atomic structure of the F9 ectodomain at 2.10 A. A structural comparison to the ectodomain of the EFC protein L1 indicated a similar fold and organization, in which a bundle of five alpha-helices is packed against two pairs of beta-strands. However, instead of the L1 myristoylation site and hydrophobic cavity, F9 possesses a protruding loop between alpha-helices alpha3 and alpha4 starting at Gly90. Gly90 is conserved in all poxviruses except Salmon gill poxvirus (SGPV) and Diachasmimorpha longicaudata entomopoxvirus. Phylogenetic sequence analysis of all Poxviridae F9 and L1 orthologs revealed the SGPV genome to contain the most distantly related F9 and L1 sequences compared to the vaccinia proteins studied here. The structural differences between F9 and L1 suggest functional adaptations during evolution from a common precursor that underlie the present requirement for each protein. The 2.1 A structure of protein F9 and its comparison to L1, two components of the conserved poxvirus entry-fusion complex.,Diesterbeck US, Gittis AG, Garboczi DN, Moss B Sci Rep. 2018 Nov 14;8(1):16807. doi: 10.1038/s41598-018-34244-7. PMID:30429486[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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