The Arg-Gly-Asp binding domain of the vitronectin receptor. Photoaffinity cross-linking implicates amino acid residues 61-203 of the beta subunit.
We have employed photoaffinity cross-linking to examine RGD recognition by the human placental vitronectin receptor. The peptide GRGDSPK was coupled to a thiol-cleavable radioiodinatable aryl azide (sulfosuccinimidyl 2-(p-azido-salicylamido)-1,3'-dithiopropionate. When 125I-sulfosuccinimidyl 2-(p-azido-salicylamido)-1,3'-dithiopropionate-GRGDSPK was cross-linked to the vitronectin receptor in solution, 80% of the label was associated with the beta subunit. Cross-linking to both subunits of the receptor was highly specific and dependent upon the presence of divalent cations. Ca2+ and Mg2+ promoted RGD recognition by the receptor; however, the effects of each divalent cation were kinetically distinct. We have also identified and determined the amino acid sequence of chymotryptic and V8 protease-generated peptides of the beta subunit that were radiolabeled as a result of cross-linking. The results of these studies demonstrate that amino acid residues 61-203 are proximal to the RGD binding domain of the vitronectin receptor.
Smith
J W
JW
Department of Immunology, Scripps Clinic and Research Foundation, La Jolla, California 92037.
Cheresh
D A
DA
D000345:Affinity Labels / Q000378:metabolism*; D000595:Amino Acid Sequence; D001386:Azides / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism*; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism*; D010449:Peptide Mapping; D010777:Photochemistry; D010782:Photolysis; D011971:Receptors, Immunologic / Q000378:metabolism*; D019030:Receptors, Vitronectin; D013388:Succinimides / Q000378:metabolism
D000345:Affinity Labels; D001386:Azides; D003432:Cross-Linking Reagents; D009842:Oligopeptides; D011971:Receptors, Immunologic; D019030:Receptors, Vitronectin; D013388:Succinimides; C057989:sulfosuccinimidyl- 2-(4-azidosalicylamido)-1,3'-dithioproprionate-glycyl-arginyl-glycyl-aspartyl-seryl-prolyl-lysine; C047981:arginyl-glycyl-aspartic acid; C047257:sulfosuccinimidyl 2-(4-azidosalicylamido)ethyl-1,3'-dithiopropionate; D008274:Magnesium; D002118:Calcium