1CK4

CRYSTAL STRUCTURE OF RAT A1B1 INTEGRIN I-DOMAIN.

Summary for 1CK4

• Entry DOI: 10.2210/pdb1ck4/pdb
• Descriptor: INTEGRIN ALPHA-1 (2 entities in total)
• Functional Keywords: i-domain, metal binding, collagen, adhesion, structural protein
• Biological source: Rattus norvegicus (Norway rat)
• Cellular location: Membrane; Single-pass type I membrane protein: P18614
• Total number of polymer chains: 2
• Total formula weight: 44236.11

Authors

Nolte, M.,Pepinsky, R.B.,Venyaminov, S.Y.,Koteliansky, V.,Gotwals, P.J.,Karpusas, M. (deposition date: 1999-04-27, release date: 2000-05-03, Last modification date: 2023-08-09)

Primary citation

Nolte, M.,Pepinsky, R.B.,Venyaminov, S.Y.u.,Koteliansky, V.,Gotwals, P.J.,Karpusas, M.
Crystal structure of the alpha1beta1 integrin I-domain: insights into integrin I-domain function.
FEBS Lett., 452:379-385, 1999

PubMed 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.

PubMed: 10386626
DOI: 10.1016/S0014-5793(99)00666-3

Experimental method

X-RAY DIFFRACTION (2.2 Å)