6cs2

Structural highlights

Function

WAC_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').SPIKE_SARS May down-regulate host tetherin (BST2) by lysosomal degradation, thereby counteracting its antiviral activity.^[1] Attaches the virion to the cell membrane by interacting with host receptor, initiating the infection (By similarity). Binding to human ACE2 and CLEC4M/DC-SIGNR receptors and internalization of the virus into the endosomes of the host cell induces conformational changes in the S glycoprotein. Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membrane fusion within endosomes.[HAMAP-Rule:MF_04099]^{[2] [3]} Mediates fusion of the virion and cellular membranes by acting as a class I viral fusion protein. Under the current model, the protein has at least three 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) 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_04099] Acts as a viral fusion peptide which is unmasked following S2 cleavage occurring upon virus endocytosis.[HAMAP-Rule:MF_04099]^[4]

See Also

• Angiotensin-Converting Enzyme 3D structures
• Fibritin
• Sandbox 3001
• Spike protein 3D structures

References

1. ↑ Wang SM, Huang KJ, Wang CT. Severe acute respiratory syndrome coronavirus spike protein counteracts BST2-mediated restriction of virus-like particle release. J Med Virol. 2019 Oct;91(10):1743-1750. doi: 10.1002/jmv.25518. Epub 2019 Jul 10. PMID:31199522 doi:http://dx.doi.org/10.1002/jmv.25518
2. ↑ Wong SK, Li W, Moore MJ, Choe H, Farzan M. A 193-amino acid fragment of the SARS coronavirus S protein efficiently binds angiotensin-converting enzyme 2. J Biol Chem. 2004 Jan 30;279(5):3197-201. Epub 2003 Dec 11. PMID:14670965 doi:http://dx.doi.org/10.1074/jbc.C300520200
3. ↑ Jeffers SA, Tusell SM, Gillim-Ross L, Hemmila EM, Achenbach JE, Babcock GJ, Thomas WD Jr, Thackray LB, Young MD, Mason RJ, Ambrosino DM, Wentworth DE, Demartini JC, Holmes KV. CD209L (L-SIGN) is a receptor for severe acute respiratory syndrome coronavirus. Proc Natl Acad Sci U S A. 2004 Nov 2;101(44):15748-53. doi:, 10.1073/pnas.0403812101. Epub 2004 Oct 20. PMID:15496474 doi:http://dx.doi.org/10.1073/pnas.0403812101
4. ↑ Belouzard S, Chu VC, Whittaker GR. Activation of the SARS coronavirus spike protein via sequential proteolytic cleavage at two distinct sites. Proc Natl Acad Sci U S A. 2009 Apr 7;106(14):5871-6. doi:, 10.1073/pnas.0809524106. Epub 2009 Mar 24. PMID:19321428 doi:http://dx.doi.org/10.1073/pnas.0809524106
5. ↑ Kirchdoerfer RN, Wang N, Pallesen J, Wrapp D, Turner HL, Cottrell CA, Corbett KS, Graham BS, McLellan JS, Ward AB. Stabilized coronavirus spikes are resistant to conformational changes induced by receptor recognition or proteolysis. Sci Rep. 2018 Oct 24;8(1):15701. doi: 10.1038/s41598-018-34171-7. PMID:30356097 doi:http://dx.doi.org/10.1038/s41598-018-34171-7