1zop

From Proteopedia

Revision as of 15:13, 15 February 2008

CD11A I-DOMAIN WITH BOUND MAGNESIUM ION

Overview

BACKGROUND: The integrin family of cell-surface receptors mediates a wide, variety of cell-cell and cell-extracellular matrix interactions., Integrin-ligand interactions are invariably dependent on the presence of, divalent cations, and a subset of integrins contain a approximately 200, amino acid inserted (I) domain that is important for ligand binding, activity and contains a single divalent cation binding site. Many, integrins are believed to respond to stimuli by undergoing a, conformational change that increases their affinity for ligand, and there, is a clear difference between two crystal structures of the CD11b I domain, with different divalent cations (magnesium and manganese) bound. In, addition to the different bound cation, a 'ligand mimetic' crystal lattice, interaction in the CD11b I domain structure with bound magnesium has led, to the interpretation that the different CD11b I domain structures, represent different affinity states of I domains. The influence of the, bound cation on I domain structure and function remains incompletely, understood, however. The crystal structure of the CD11a I domain bound to, manganese is known. We therefore set out to determine whether this, structure changes when the metal ion is altered or removed. RESULTS: We, report here the crystal structures of the CD11a I domain determined in the, absence of bound metal ion and with bound magnesium ion. No major, structural rearrangements are observed in the metal-binding site of the, CD11a I domain in the absence or presence of bound manganese ion. The, structures of the CD11a I domain with magnesium or manganese bound are, extremely similar. CONCLUSIONS: The conformation of the CD11a I domain is, not altered by changes in metal ion binding. The cation-dependence of, ligand binding thus indicates that the metal ion is either involved in, direct interaction with ligand or required to promote a favorable, quaternary arrangement of the integrin.

About this Structure

1ZOP is a Single protein structure of sequence from Homo sapiens with and as ligands. Full crystallographic information is available from OCA.

Reference

The role of the divalent cation in the structure of the I domain from the CD11a/CD18 integrin., Qu A, Leahy DJ, Structure. 1996 Aug 15;4(8):931-42. PMID:8805579

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