2oz4

From Proteopedia

proteopedia linkproteopedia link

spinqualitylabelsall models 2oz4, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structural Plasticity in IgSF Domain 4 of ICAM-1 Mediates Cell Surface Dimerization

Overview

The Ig superfamily (IgSF) intercellular adhesion molecule-1 (ICAM-1), equilibrates between monomeric and dimeric forms on the cell surface, and, dimerization enhances cell adhesion. A crystal structure of ICAM-1 IgSF, domains (D) 3-5 revealed a unique dimerization interface in which D4s of, two protomers fuse through edge beta-strands to form a single super, beta-sandwich domain. Here, we describe a crystal structure at 2.7-A, resolution of monomeric ICAM-1 D3-D5, stabilized by the monomer-specific, Fab CA7. CA7 binds to D5 in a region that is buried in the dimeric, interface and is distal from the dimerization site in D4. In monomeric, ICAM-1 D3-D5, a 16-residue loop in D4 that is disordered in the dimeric, structure could clearly be traced as a BC loop, a short C strand, and a CE, meander with a cis-Pro followed by a solvent-exposed, flexible, four-residue region. Deletions of 6 or 10 residues showed that the, C-strand is essential for monomer stability, whereas a distinct, six-residue deletion showed little contribution of the CE meander., Mutation of two inward-pointing Leu residues in edge beta-strand E to Lys, increased monomer stability, confirming the hypothesis that, inward-pointing charged side chains on edge beta-strands are an important, design feature to prevent beta-supersheet formation. Overall, the studies, reveal that monomer-dimer transition is associated with a surprisingly, large, physiologically relevant, IgSF domain rearrangement.

About this Structure

2OZ4 is a Single protein structure of sequence from Homo sapiens and Mus musculus with , , and as ligands. Full crystallographic information is available from OCA.

Reference

Structural plasticity in Ig superfamily domain 4 of ICAM-1 mediates cell surface dimerization., Chen X, Kim TD, Carman CV, Mi LZ, Song G, Springer TA, Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15358-63. Epub 2007 Sep 19. PMID:17881562

Page seeded by OCA on Wed Jan 23 12:53:33 2008