1ck4
CRYSTAL STRUCTURE OF RAT A1B1 INTEGRIN I-DOMAIN.
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| , resolution 2.20Å | |||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
The alpha1beta1 integrin is a major cell surface receptor for collagen. Ligand binding is mediated, in part, through a 200 amino acid inserted 'I'-domain contained in the extracellular part of the integrin alpha chain. Integrin I-domains contain a divalent cation binding (MIDAS) site and require cations to interact with integrin ligands. We have determined the crystal structure of recombinant I-domain from the rat alpha1beta1 integrin at 2.2 A resolution in the absence of divalent cations. The alpha1 I-domain adopts the dinucleotide binding fold that is characteristic of all I-domain structures that have been solved to date and has a structure very similar to that of the closely related alpha2beta1 I-domain which also mediates collagen binding. A unique feature of the alpha1 I-domain crystal structure is that the MIDAS site is occupied by an arginine side chain from another I-domain molecule in the crystal, in place of a metal ion. This interaction supports a proposed model for ligand-induced displacement of metal ions. Circular dichroism spectra determined in the presence of Ca2+, Mg2+ and Mn2+ indicate that no changes in the structure of the I-domain occur upon metal ion binding in solution. Metal ion binding induces small changes in UV absorption spectra, indicating a change in the polarity of the MIDAS site environment.
About this StructureAbout this Structure
1CK4 is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the alpha1beta1 integrin I-domain: insights into integrin I-domain function., Nolte M, Pepinsky RB, Venyaminov SYu, Koteliansky V, Gotwals PJ, Karpusas M, FEBS Lett. 1999 Jun 11;452(3):379-85. PMID:10386626
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