Model of the αLβ2 integrin I-domain/ICAM-1 DI interface suggests that subtle changes in loop orientation determine ligand specificity

Glen B. Legge, Garrett M. Morris, Michel F. Sanner, Yoshikazu Takada, Arthur J. Olson, Flavio Grynszpan

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The interaction of the αLβ2 integrin with its cellular ligand the intercellular adhesion molecule-1 (ICAM-1) is critical for the tight binding interaction between most leukocytes and the vascular endothelium before transendothelial migration to the sites of inflammation. In this article we have modeled the αL subunit I-domain in its active form, which was computationally docked with the D1 domain of the ICAM-1 to probe potential protein-protein interactions. The experimentally observed key interaction between the carboxylate of Glu 34 in the ICAM-1 D1 domain and the metal ion-dependent adhesion site (MIDAS) in the open αL I-domain was consistently reproduced by our calculations. The calculations reveal the nature of the αLβ2/ICAM-1 interaction and suggest an explanation for the increased ligand-binding affinity in the "open" versus the "closed" conformation of the αL I-domain. A mechanism for substrate selectivity among αL, αM, and α2 I-domains is suggested whereby the orientation of the loops within the I-domain is critical in mediating the interaction of the Glu 34 carboxylate of ICAM-1 D1 with the MIDAS.

Original languageEnglish (US)
Pages (from-to)151-160
Number of pages10
JournalProteins: Structure, Function and Genetics
Volume48
Issue number2
DOIs
StatePublished - Aug 1 2002
Externally publishedYes

Keywords

  • αL I-domain
  • Docking
  • ICAM-1
  • Integrin, activation
  • Modeling

ASJC Scopus subject areas

  • Genetics
  • Structural Biology
  • Biochemistry

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