Structural highlights
Function
[SPIKE_BCHK5] S1 region attaches the virion to the cell membrane by interacting with cell receptors, initiating the infection. S2 is a 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) 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 (By similarity).
Publication Abstract from PubMed
Accumulating evidence indicates that MERS-CoV originated from bat coronaviruses (BatCoVs). Previously, we demonstrated that both MERS-CoV and BatCoV HKU4 use CD26 as a receptor, but how the BatCoVs evolved to bind CD26 is an intriguing question. Here, we solved the crystal structure of the S1 subunit C-terminal domain of HKU5 (HKU5-CTD), another BatCoV that is phylogenetically related to MERS-CoV but cannot bind to CD26. We observed that the conserved core subdomain and those of other betacoronaviruses (betaCoVs) have a similar topology of the external subdomain, indicating the same ancestor of lineage C betaCoVs. However, two deletions in two respective loops located in HKU5-CTD result in conformational variations in CD26-binding interface and are responsible for the non-binding of HKU5-CTD to CD26. Combined with sequence variation in the HKU5-CTD receptor binding interface, we propose the necessity for surveilling the mutation in BatCoV HKU5 spike protein in case of bat-to-human interspecies transmission.
Structure of the S1 subunit C-terminal domain from bat-derived coronavirus HKU5 spike protein.,Han X, Qi J, Song H, Wang Q, Zhang Y, Wu Y, Lu G, Yuen KY, Shi Y, Gao GF Virology. 2017 Apr 19;507:101-109. doi: 10.1016/j.virol.2017.04.016. PMID:28432925[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Han X, Qi J, Song H, Wang Q, Zhang Y, Wu Y, Lu G, Yuen KY, Shi Y, Gao GF. Structure of the S1 subunit C-terminal domain from bat-derived coronavirus HKU5 spike protein. Virology. 2017 Apr 19;507:101-109. doi: 10.1016/j.virol.2017.04.016. PMID:28432925 doi:http://dx.doi.org/10.1016/j.virol.2017.04.016
