1qc5
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I DOMAIN FROM INTEGRIN ALPHA1-BETA1
OverviewOverview
Most mammalian cells and some pathogenic bacteria are capable of adhering, to collagenous substrates in processes mediated by specific cell surface, adherence molecules. Crystal structures of collagen-binding regions of the, human integrin alpha(2)beta(1) and a Staphylococcus aureus adhesin reveal, a "trench" on the surface of both of these proteins. This trench can, accommodate a collagen triple-helical structure and presumably represents, the ligand-binding site (Emsley, J., King, S. L., Bergelson, J. M., and, Liddington, R. C. (1997) J. Biol. Chem. 272, 28512-28517; Symersky, J., Patti, J. M., Carson, M., House-Pompeo, K., Teale, M., Moore, D., Jin, L., Schneider, A., DeLucas, L. J., Hook, M., and Narayana, S. V. L. (1997), Nat. Struct. Biol. 4, 833-838). We report here the crystal structure of, the alpha subunit I domain from the alpha(1)beta(1) integrin. This, collagen-binding protein also contains a trench on one face in which the, collagen triple helix may be docked. Furthermore, we compare the, collagen-binding mechanisms of the human alpha(1) integrin I domain and, the A domain from the S. aureus collagen adhesin, Cna. Although the S., aureus and human proteins have unrelated amino acid sequences, secondary, structure composition, and cation requirements for effective ligand, binding, both proteins bind at multiple sites within one collagen, molecule, with the sites in collagen varying in their affinity for the, adherence molecule. We propose that (i) these evolutionarily dissimilar, adherence proteins recognize collagen via similar mechanisms, (ii) the, multisite, multiclass protein/ligand interactions observed in these two, systems result from a binding-site trench, and (iii) this unusual binding, mechanism may be thematic for proteins binding extended, rigid ligands, that contain repeating structural motifs.
About this StructureAbout this Structure
1QC5 is a Protein complex structure of sequences from Homo sapiens with MG as ligand. Structure known Active Site: MGA. Full crystallographic information is available from OCA.
ReferenceReference
Trench-shaped binding sites promote multiple classes of interactions between collagen and the adherence receptors, alpha(1)beta(1) integrin and Staphylococcus aureus cna MSCRAMM., Rich RL, Deivanayagam CC, Owens RT, Carson M, Hook A, Moore D, Symersky J, Yang VW, Narayana SV, Hook M, J Biol Chem. 1999 Aug 27;274(35):24906-13. PMID:10455165
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