Directed evolution to probe protein allostery and integrin I domains of 200,000-fold higher affinity

Moonsoo Jin, Gang Song, Christopher V. Carman, Yong Sung Kim, Nathan S. Astrof, Motomu Shimaoka, Dane K. Wittrup, Timothy A. Springer

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Understanding allostery may serve to both elucidate mechanisms of protein regulation and provide a basis for engineering active mutants. Herein we describe directed evolution applied to the integrin αL inserted domain for studying allostery by using a yeast surface display system. Many hot spots for activation are identified, and some single mutants exhibit remarkable increases of 10,000-fold in affinity for a physiological ligand, intercellular adhesion molecule-1. The location of activating mutations traces out an allosteric interface in the interior of the inserted domain that connects the ligand binding site to the α7-helix, which communicates allostery to neighboring domains in intact integrins. The combination of two activating mutations (F265S/F292G) leads to an increase of 200,000-fold in affinity to intercellular adhesion molecule-1. The F265S/F292G mutant is potent in antagonizing lymphocyte function-associated antigen 1-dependent lymphocyte adhesion, aggregation, and transmigration.

Original languageEnglish (US)
Pages (from-to)5758-5763
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number15
StatePublished - Apr 11 2006

ASJC Scopus subject areas

  • General


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