Back to Search
Start Over
Crystal structure of the alpha1beta1 integrin I-domain: insights into integrin I-domain function.
- Source :
-
FEBS letters [FEBS Lett] 1999 Jun 11; Vol. 452 (3), pp. 379-85. - Publication Year :
- 1999
-
Abstract
- 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.
Details
- Language :
- English
- ISSN :
- 0014-5793
- Volume :
- 452
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- FEBS letters
- Publication Type :
- Academic Journal
- Accession number :
- 10386626
- Full Text :
- https://doi.org/10.1016/s0014-5793(99)00666-3