2zg3

From Proteopedia

Crystal Structure of Two N-terminal Domains of Native Siglec-5 in Complex with 3'-Sialyllactose

PDB ID 2zg3

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Structural highlights

2zg3 is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SIGL5_HUMAN Putative adhesion molecule that mediates sialic-acid dependent binding to cells. Binds equally to alpha-2,3-linked and alpha-2,6-linked sialic acid. The sialic acid recognition site may be masked by cis interactions with sialic acids on the same cell surface.

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

Sialic acid (Sia) Ig-like binding lectins are important mediators of recognition and signaling events among myeloid cells. To investigate the molecular mechanism underlying sialic acid Ig-like lectin (Siglec) functions, we determined the crystal structure of the two N-terminal extracellular domains of human myeloid cell inhibitory receptor Siglec-5 (CD170) and its complexes with two sialylated carbohydrates. The native structure revealed an unusual conformation of the CC' ligand specificity loop and a unique interdomain disulfide bond. The alpha(2,3)- and alpha(2,6)-sialyllactose complexed structures showed a conserved Sia recognition motif that involves both Arg124 and a portion of the G-strand in the V-set domain forming beta-sheet-like hydrogen bonds with the glycerol side chain of the Sia. Only few protein contacts to the subterminal sugars are observed and mediated by the highly variable GG' linker and CC' loop. These structural observations, in conjunction with surface plasmon resonance binding assays, provide mechanistic insights into linkage-dependent Siglec carbohydrate recognition and suggest that Siglec-5 and other CD33-related Siglec receptors are more promiscuous in sialoglycan recognition than previously understood.

Structural implications of Siglec-5-mediated sialoglycan recognition.,Zhuravleva MA, Trandem K, Sun PD J Mol Biol. 2008 Jan 11;375(2):437-47. Epub 2007 Oct 11. PMID:18022638^[1]

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

References

↑ Zhuravleva MA, Trandem K, Sun PD. Structural implications of Siglec-5-mediated sialoglycan recognition. J Mol Biol. 2008 Jan 11;375(2):437-47. Epub 2007 Oct 11. PMID:18022638 doi:http://dx.doi.org/10.1016/j.jmb.2007.10.009