==Structure of SARS coronavirus spike receptor-binding domain complexed with its receptor==

<StructureSection load='2ajf' size='340' side='right' caption='[[2ajf]], [[Resolution|resolution]] 2.90&Aring;' scene=''>

<table><tr><td colspan='2'>[[2ajf]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Cvhsa Cvhsa] and [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AJF OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2AJF FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2ajf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2ajf OCA], [http://pdbe.org/2ajf PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2ajf RCSB], [http://www.ebi.ac.uk/pdbsum/2ajf PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2ajf ProSAT]</span></td></tr>

== Function ==

[[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> [[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.

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== Publication Abstract from PubMed ==

The spike protein (S) of SARS coronavirus (SARS-CoV) attaches the virus to its cellular receptor, angiotensin-converting enzyme 2 (ACE2). A defined receptor-binding domain (RBD) on S mediates this interaction. The crystal structure at 2.9 angstrom resolution of the RBD bound with the peptidase domain of human ACE2 shows that the RBD presents a gently concave surface, which cradles the N-terminal lobe of the peptidase. The atomic details at the interface between the two proteins clarify the importance of residue changes that facilitate efficient cross-species infection and human-to-human transmission. The structure of the RBD suggests ways to make truncated disulfide-stabilized RBD variants for use in the design of coronavirus vaccines.

Structure of SARS coronavirus spike receptor-binding domain complexed with receptor.,Li F, Li W, Farzan M, Harrison SC Science. 2005 Sep 16;309(5742):1864-8. PMID:16166518<ref>PMID:16166518</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 2ajf" style="background-color:#fffaf0;"></div>

==See Also==

*[[Angiotensin-Converting Enzyme|Angiotensin-Converting Enzyme]]

== References ==

<references/>

[[Category: Cvhsa]]

[[Category: Human]]

[[Category: Hydrolase-viral protein complex]]