1olz

File:1olz.jpg

THE LIGAND-BINDING FACE OF THE SEMAPHORINS REVEALED BY THE HIGH RESOLUTION CRYSTAL STRUCTURE OF SEMA4D

OverviewOverview

Semaphorins, proteins characterized by an extracellular sema domain, regulate axon guidance, immune function and angiogenesis. The crystal structure of SEMA4D (residues 1-657) shows the sema topology to be a seven-bladed beta-propeller, revealing an unexpected homology with integrins. The sema beta-propeller contains a distinctive 77-residue insertion between beta-strands C and D of blade 5. Blade 7 is followed by a domain common to plexins, semaphorins and integrins (PSI domain), which forms a compact cysteine knot abutting the side of the propeller, and an Ig-like domain. The top face of the beta-propeller presents prominent loops characteristic of semaphorins. In addition to limited contact between the Ig-like domains, the homodimer is stabilized through extensive interactions between the top faces in a sector of the beta-propeller used for heterodimerization in integrins. This face of the propeller also mediates ligand binding in integrins, and functional data for semaphorin-receptor interactions map to the equivalent surface.

About this StructureAbout this Structure

1OLZ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

ReferenceReference

The ligand-binding face of the semaphorins revealed by the high-resolution crystal structure of SEMA4D., Love CA, Harlos K, Mavaddat N, Davis SJ, Stuart DI, Jones EY, Esnouf RM, Nat Struct Biol. 2003 Oct;10(10):843-8. Epub 2003 Sep 7. PMID:12958590 Page seeded by OCA on Sun Apr 13 08:08:23 2008