4WK2

Metal Ion and Ligand Binding of Integrin

4WK2 の概要

• エントリーDOI: 10.2210/pdb4wk2/pdb
• 関連するPDBエントリー: 4WJK 4WK0 4WK4
• 分子名称: Integrin alpha-5, Integrin beta-1, GLY-ARG-GLY-ASP-SER-PRO, ... (10 entities in total)
• 機能のキーワード: cell adhesion-fibronectin receptor, cell adhesion-immune system complex, cell adhesion/immune system
• 由来する生物種: Homo sapiens (Human); 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 103039.30

構造登録者

Xia, W.,Springer, T.A. (登録日: 2014-10-01, 公開日: 2014-12-03, 最終更新日: 2024-11-20)

主引用文献

Xia, W.,Springer, T.A.
Metal ion and ligand binding of integrin alpha 5 beta 1.
Proc.Natl.Acad.Sci.USA, 111:17863-17868, 2014

PubMed Abstract: Integrin α5β1 binds to an Arg-Gly-Asp (RGD) motif in its ligand fibronectin. We report high-resolution crystal structures of a four-domain α5β1 headpiece fragment, alone or with RGD peptides soaked into crystals, and RGD peptide affinity measurements. The headpiece crystallizes in a closed conformation essentially identical to that seen previously for α5β1 complexed with a Fab that allosterically inhibits ligand binding by stabilizing the closed conformation. Soaking experiments show that binding of cyclic RGD peptide with 20-fold higher affinity than a linear RGD peptide induces conformational change in the β1-subunit βI domain to a state that is intermediate between closed (low affinity) and open (high affinity). In contrast, binding of a linear RGD peptide induces no shape shifting. However, linear peptide binding induces shape shifting when Ca(2+) is depleted during soaking. Ca(2+) bound to the adjacent to metal ion-dependent adhesion site (ADMIDAS), at the locus of shape shifting, moves and decreases in occupancy, correlating with an increase in affinity for RGD measured when Ca(2+) is depleted. The results directly demonstrate that Ca(2+) binding to the ADMIDAS stabilizes integrins in the low-affinity, closed conformation. Comparisons in affinity between four-domain and six-domain headpiece constructs suggest that flexible integrin leg domains contribute to conformational equilibria. High-resolution views of the hybrid domain interface with the plexin-semaphorin-integrin (PSI) domain in different orientations show a ball-and-socket joint with a hybrid domain Arg side chain that rocks in a PSI domain socket lined with carbonyl oxygens.

PubMed: 25475857
DOI: 10.1073/pnas.1420645111

実験手法

X-RAY DIFFRACTION (2.5 Å)