W. Puzonmclaughlin et Y. Takada, CRITICAL RESIDUES FOR LIGAND-BINDING IN AN I-DOMAIN-LIKE STRUCTURE OFTHE INTEGRIN BETA-1 SUBUNIT, The Journal of biological chemistry, 271(34), 1996, pp. 20438-20443
Several integrin alpha subunits have an inserted sequence of about 200
residues (the I or A domain) that is critical for ligand interactions
. The presence of an I domain-like structure within the integrin beta
subunit has been proposed based on the similarity of the hydropathy pr
ofiles and the homology of sequences between the alpha and beta subuni
ts. This study was designed to determine whether the region of the bet
a 1 subunit that includes residues 101-335 has the characteristics of
an I domain. We found novel critical residues for ligand binding (Ser-
132, Asn-224, Asp-226, Glu-229, Asp-233, Asp-267, and Asp-295, in addi
tion to the previously reported Asp-130) using site-directed mutagenes
is, The critical residues for ligand binding are located in several of
loop structures of the region (or in a potential loop between an alph
a helix and a beta strand), which have been predicted using multiple s
econdary structure prediction methods. The data suggest that the beta
subunit has multiple disrupted critical oxygenated residues for ligand
binding similar to those found in the alpha I domain.