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3i27

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Revision as of 16:15, 25 December 2014

Structure of bovine torovirus Hemagglutinin-Esterase in complex with receptor

Structural highlights

3i27 is a 4 chain structure with sequence from Breda virus serotype 1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:	, , ,
Related:	3i1k, 3i1l, 3i26
Gene:	HE (Breda virus serotype 1)
Activity:	Sialate O-acetylesterase, with EC number 3.1.1.53
Resources:	FirstGlance, OCA, RCSB, PDBsum

Function

[HEMA_BRV1] Structural protein that makes short spikes at the surface of the virus. Contains receptor binding and receptor-destroying activities. Mediates de-O-acetylation of N-acetyl-9-di-O-acetylneuraminic acid, which is probably the receptor determinant recognized by the virus on the surface of erythrocytes and susceptible cells. Also hydrolyzes 5-N-acetyl-4-O-acetylneuramic acid and N-acetyl-9-O-acetylneuraminic acid, but displays a substrate preference for N-acetyl-9-di-O-acetylneuraminic acid. This receptor-destroying activity is important for virus release as it probably helps preventing self-aggregation and ensures the efficient spread of the progeny virus from cell to cell. May serve as a secondary viral attachment protein for initiating infection, the spike protein being the major one. Seems to be a 'luxury' protein that is not absolutely necessary for virus infection in culture. However, its presence in the virus may alter its pathogenicity. May become a target for both the humoral and the cellular branches of the immune system.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Hemagglutinin esterases (HEs), closely related envelope glycoproteins in influenza C and corona- and toroviruses, mediate reversible attachment to O-acetylated sialic acids (Sias). They do so by acting both as lectins and as receptor-destroying enzymes, functions exerted by separate protein domains. HE divergence was accompanied by changes in quaternary structure and in receptor and substrate specificity. The selective forces underlying HE diversity and the molecular basis for Sia specificity are poorly understood. Here we present crystal structures of porcine and bovine torovirus HEs in complex with receptor analogs. Torovirus HEs form homodimers with sialate-O-acetylesterase domains almost identical to corresponding domains in orthomyxo- and coronavirus HEs, but with unique lectin sites. Structure-guided biochemical analysis of the esterase domains revealed that a functionally, but not structurally conserved arginine-Sia carboxylate interaction is critical for the binding and positioning of glycosidically bound Sias in the catalytic pocket. Although essential for efficient de-O-acetylation of Sias, this interaction is not required for catalysis nor does it affect substrate specificity. In fact, the distinct preference of the porcine torovirus enzyme for 9-mono- over 7,9-di-O-acetylated Sias can be explained from a single-residue difference with HEs of more promiscuous specificity. Apparently, esterase and lectin pockets coevolved; also the porcine torovirus HE receptor-binding site seems to have been designed to use 9-mono- and exclude di-O-acetylated Sias, possibly as an adaptation to replication in swine. Our findings shed light on HE evolution and provide fundamental insight into mechanisms of substrate binding, substrate recognition, and receptor selection in this important class of virion proteins.

Structural basis for ligand and substrate recognition by torovirus hemagglutinin esterases.,Langereis MA, Zeng Q, Gerwig GJ, Frey B, von Itzstein M, Kamerling JP, de Groot RJ, Huizinga EG Proc Natl Acad Sci U S A. 2009 Aug 31. PMID:19721004^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Langereis MA, Zeng Q, Gerwig GJ, Frey B, von Itzstein M, Kamerling JP, de Groot RJ, Huizinga EG. Structural basis for ligand and substrate recognition by torovirus hemagglutinin esterases. Proc Natl Acad Sci U S A. 2009 Aug 31. PMID:19721004

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 See Also
6 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/3i27"

@@ Line 9: / Line 9: @@
 <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=3i27 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3i27 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3i27 RCSB], [http://www.ebi.ac.uk/pdbsum/3i27 PDBsum]</span></td></tr>
 </table>
+== Function ==
+[[http://www.uniprot.org/uniprot/HEMA_BRV1 HEMA_BRV1]] Structural protein that makes short spikes at the surface of the virus. Contains receptor binding and receptor-destroying activities. Mediates de-O-acetylation of N-acetyl-9-di-O-acetylneuraminic acid, which is probably the receptor determinant recognized by the virus on the surface of erythrocytes and susceptible cells. Also hydrolyzes 5-N-acetyl-4-O-acetylneuramic acid and N-acetyl-9-O-acetylneuraminic acid, but displays a substrate preference for N-acetyl-9-di-O-acetylneuraminic acid. This receptor-destroying activity is important for virus release as it probably helps preventing self-aggregation and ensures the efficient spread of the progeny virus from cell to cell. May serve as a secondary viral attachment protein for initiating infection, the spike protein being the major one. Seems to be a 'luxury' protein that is not absolutely necessary for virus infection in culture. However, its presence in the virus may alter its pathogenicity. May become a target for both the humoral and the cellular branches of the immune system.
 == Evolutionary Conservation ==
 [[Image:Consurf_key_small.gif|200px|right]]

3i27

From Proteopedia

Revision as of 16:15, 25 December 2014

Structure of bovine torovirus Hemagglutinin-Esterase in complex with receptor

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

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