6jx7
From Proteopedia
Cryo-EM structure of spike protein of feline infectious peritonitis virus strain UU4
Structural highlights
FunctionWAC_BPT4 Chaperone responsible for attachment of long tail fibers to virus particle. Forms the fibrous structure on the neck of the virion called whiskers. During phage assembly, 6 fibritin molecules attach to each virion neck through their N-terminal domains, to form a collar with six fibers ('whiskers').C6GHB7_9ALPC S1 region attaches the virion to the cell membrane by interacting with the host receptor, initiating the infection. Binding to the receptor probably induces conformational changes in the S glycoprotein unmasking the fusion peptide of S2 region and activating membranes fusion. S2 region belongs to the class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) regions assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes.[HAMAP-Rule:MF_04200] Publication Abstract from PubMedFeline infectious peritonitis virus (FIPV) is an alphacoronavirus that causes a nearly 100% mortality rate without effective treatment. Here we report a 3.3-A cryoelectron microscopy (cryo-EM) structure of the serotype I FIPV spike (S) protein, which is responsible for host recognition and viral entry. Mass spectrometry provided site-specific compositions of densely distributed high-mannose and complex-type N-glycans that account for 1/4 of the total molecular mass; most of the N-glycans could be visualized by cryo-EM. Specifically, the N-glycans that wedge between 2 galectin-like domains within the S1 subunit of FIPV S protein result in a unique propeller-like conformation, underscoring the importance of glycosylation in maintaining protein structures. The cleavage site within the S2 subunit responsible for activation also showed distinct structural features and glycosylation. These structural insights provide a blueprint for a better molecular understanding of the pathogenesis of FIP. Cryo-EM analysis of a feline coronavirus spike protein reveals a unique structure and camouflaging glycans.,Yang TJ, Chang YC, Ko TP, Draczkowski P, Chien YC, Chang YC, Wu KP, Khoo KH, Chang HW, Hsu SD Proc Natl Acad Sci U S A. 2020 Jan 21;117(3):1438-1446. doi:, 10.1073/pnas.1908898117. Epub 2020 Jan 3. PMID:31900356[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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