View source for 6acj


==Trypsin-cleaved and low pH-treated SARS-CoV spike glycoprotein and ACE2 complex, ACE2-bound conformation 2==
<SX load='6acj' size='340' side='right' viewer='molstar' caption='[[6acj]], [[Resolution|resolution]] 4.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6acj]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/ ] and [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6ACJ OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6ACJ FirstGlance]. <br>
</td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">ACE2, UNQ868/PRO1885 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Angiotensin-converting_enzyme_2 Angiotensin-converting enzyme 2], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.17.23 3.4.17.23] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6acj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6acj OCA], [http://pdbe.org/6acj PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6acj RCSB], [http://www.ebi.ac.uk/pdbsum/6acj PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6acj ProSAT]</span></td></tr>
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== Function ==
[[http://www.uniprot.org/uniprot/SPIKE_CVHSA SPIKE_CVHSA]] S1 attaches the virion to the cell membrane by interacting with human ACE2 and CLEC4M/DC-SIGNR, initiating the infection. Binding to the receptor and internalization of the virus into the endosomes of the host cell probably induces conformational changes in the S glycoprotein. Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membranes fusion within endosomes.  S2 is 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. [[http://www.uniprot.org/uniprot/ACE2_HUMAN ACE2_HUMAN]] Carboxypeptidase which converts angiotensin I to angiotensin 1-9, a peptide of unknown function, and angiotensin II to angiotensin 1-7, a vasodilator. Also able to hydrolyze apelin-13 and dynorphin-13 with high efficiency. May be an important regulator of heart function. In case of human coronaviruses SARS and HCoV-NL63 infections, serve as functional receptor for the spike glycoprotein of both coronaviruses.<ref>PMID:10969042</ref> <ref>PMID:10924499</ref> <ref>PMID:14647384</ref>  
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== Publication Abstract from PubMed ==
The trimeric SARS coronavirus (SARS-CoV) surface spike (S) glycoprotein consisting of three S1-S2 heterodimers binds the cellular receptor angiotensin-converting enzyme 2 (ACE2) and mediates fusion of the viral and cellular membranes through a pre- to postfusion conformation transition. Here, we report the structure of the SARS-CoV S glycoprotein in complex with its host cell receptor ACE2 revealed by cryo-electron microscopy (cryo-EM). The complex structure shows that only one receptor-binding domain of the trimeric S glycoprotein binds ACE2 and adopts a protruding "up" conformation. In addition, we studied the structures of the SARS-CoV S glycoprotein and its complexes with ACE2 in different in vitro conditions, which may mimic different conformational states of the S glycoprotein during virus entry. Disassociation of the S1-ACE2 complex from some of the prefusion spikes was observed and characterized. We also characterized the rosette-like structures of the clustered SARS-CoV S2 trimers in the postfusion state observed on electron micrographs. Structural comparisons suggested that the SARS-CoV S glycoprotein retains a prefusion architecture after trypsin cleavage into the S1 and S2 subunits and acidic pH treatment. However, binding to the receptor opens up the receptor-binding domain of S1, which could promote the release of the S1-ACE2 complex and S1 monomers from the prefusion spike and trigger the pre- to postfusion conformational transition.

Cryo-EM structure of the SARS coronavirus spike glycoprotein in complex with its host cell receptor ACE2.,Song W, Gui M, Wang X, Xiang Y PLoS Pathog. 2018 Aug 13;14(8):e1007236. doi: 10.1371/journal.ppat.1007236. PMID:30102747<ref>PMID:30102747</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6acj" style="background-color:#fffaf0;"></div>

==See Also==
*[[Angiotensin-Converting Enzyme 3D structures|Angiotensin-Converting Enzyme 3D structures]]
*[[Spike protein|Spike protein]]
== References ==
<references/>
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</SX>
[[Category: Angiotensin-converting enzyme 2]]
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Gui, M]]
[[Category: Song, W]]
[[Category: Class i fusion protein]]
[[Category: Glycoprotein]]
[[Category: Membrane fusion]]
[[Category: Sars-cov]]
[[Category: Spike]]
[[Category: Viral protein]]
[[Category: Viral protein-hydrolase complex]]