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1zxq
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(New page: 200px<br /> <applet load="1zxq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zxq, resolution 2.2Å" /> '''THE CRYSTAL STRUCTUR...)
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Revision as of 18:36, 12 November 2007
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THE CRYSTAL STRUCTURE OF ICAM-2
Overview
Recognition by integrin proteins on the cell surface regulates the, adhesive interactions between cells and their surroundings. The structure, of the 'I' domain that is found in some but not all integrins, has been, determined. However, the only integrin ligands for which structures are, known, namely fibronectin and VCAM-1, are recognized by integrins that, lack I domains. The intercellular adhesion molecules ICAM-1, 2 and 3 are, like VCAM-1, members of the immunoglobulin superfamily (IgSF), but they, are recognized by an I domain-containing integrin, lymphocyte-function-associated antigen 1 (LFA-1, or CD11a/CD18). Here we, present the crystal structure of the extracellular region of ICAM-2. The, glutamic acid residue at position 37 is critical for LFA-1 binding and is, proposed to coordinate the Mg2+ ion in the I domain; this Glu 37 is, surrounded by a relatively flat recognition surface and lies in a, beta-strand, whereas the critical aspartic acid residue in VCAM-1 and, fibronectin lie in protruding loops. This finding suggests that there are, differences in the architecture of recognition sites between integrins, that contain or lack I domains. A bend between domains 1 and 2 of ICAM-2, and a tripod-like arrangement of N-linked glycans in the membrane-proximal, region of domain 2 may be important for presenting the recognition surface, to LFA-1. A model of ICAM-1 based on the ICAM-2 structure provides a, framework for understanding its recognition by pathogens.
About this Structure
1ZXQ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structure of ICAM-2 reveals a distinctive integrin recognition surface., Casasnovas JM, Springer TA, Liu JH, Harrison SC, Wang JH, Nature. 1997 May 15;387(6630):312-5. PMID:9153399
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