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Publication Abstract from PubMed

Integrins are important therapeutic targets. However, current RGD-based anti-integrin drugs are also partial agonists, inducing conformational changes that trigger potentially fatal immune reactions and paradoxical cell adhesion. Here we describe the first crystal structure of alphaVbeta3 bound to a physiologic ligand, the tenth type III RGD domain of wild-type fibronectin (wtFN10), or to a high-affinity mutant (hFN10) shown here to act as a pure antagonist. Comparison of these structures revealed a central pi-pi interaction between Trp1496 in the RGD-containing loop of hFN10 and Tyr122 of the beta3 subunit that blocked conformational changes triggered by wtFN10 and trapped hFN10-bound alphaVbeta3 in an inactive conformation. Removing the Trp1496 or Tyr122 side chains or reorienting Trp1496 away from Tyr122 converted hFN10 into a partial agonist. These findings offer new insights into the mechanism of integrin activation and a basis for the design of RGD-based pure antagonists.

Structural basis for pure antagonism of integrin alphaVbeta3 by a high-affinity form of fibronectin.,Van Agthoven JF, Xiong JP, Alonso JL, Rui X, Adair BD, Goodman SL, Arnaout MA Nat Struct Mol Biol. 2014 Apr;21(4):383-8. doi: 10.1038/nsmb.2797. Epub 2014 Mar , 23. PMID:24658351^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.