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1N9Z

INTEGRIN ALPHA M I DOMAIN MUTANT

Summary for 1N9Z
Entry DOI10.2210/pdb1n9z/pdb
Related1IDO
DescriptorIntegrin alpha-M, MAGNESIUM ION (2 entities in total)
Functional Keywordsrossmann fold, cell adhesion
Biological sourceHomo sapiens (human)
Cellular locationMembrane; Single-pass type I membrane protein: P11215
Total number of polymer chains1
Total formula weight22004.48
Authors
McCleverty, C.J.,Liddington, R.C. (deposition date: 2002-11-26, release date: 2003-05-20, Last modification date: 2023-08-16)
Primary citationMcCleverty, C.J.,Liddington, R.C.
Engineered allosteric mutants of the integrin alphaMbeta2 I domain: structural and functional studies
Biochem.J., 372:121-127, 2003
Cited by
PubMed Abstract: The alpha-I domain, found in the alpha-subunit of the leucocyte integrins such as alphaMbeta2 and alphaLbeta2, switches between the open and closed tertiary conformations, reflecting the high- and low-affinity ligand-binding states of the integrin that are required for regulated cell adhesion and migration. In the present study we show, by using point mutations and engineered disulphide bonds, that ligand affinity can be reduced or increased allosterically by altering the equilibrium between the closed and open states. We determined equilibrium constants for the binding of two ligands, fibrinogen and intercellular cell-adhesion molecule 1, to the alphaM-I domain by surface plasmon resonance, and determined crystal structures of a low-affinity mutant. Locking the domain in the open conformation increases affinity by a factor of no greater than 10, consistent with a closely balanced equilibrium between the two conformations in the absence of ligand. This behaviour contrasts with that of the unliganded alphaL-I domain, for which the equilibrium lies strongly in favour of the closed conformation. These results suggest significant differences in the way the parent integrins regulate I domain conformation and hence ligand affinity.
PubMed: 12611591
DOI: 10.1042/BJ20021273
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (2.5 Å)
Structure validation

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