PDBsum entry: 1q7d

Contractile protein

PDB id: 1q7d

Contents

Protein chains

23 a.a.

21 a.a.

Waters ×94

PDB id:

1q7d

Name:

Contractile protein

Title:

Structure of the integrin alpha2beta1 binding collagen peptide

Structure:

Collagen alfa 1(i) chain peptide gpogpogfogergpogpogpo. Chain: a, b, c. Engineered: yes

Source:

Synthetic: yes. Other_details: the peptide was chemically synthesized. The sequence of the peptide is naturally found in homo sapiens (human). Peptide synthesised using standard fmoc synthesis

Biol. unit:

Trimer (from PQS)

Resolution:

1.80Å R-factor: 0.236 R-free: 0.266

Authors:

J.Emsley,C.G.Knight,R.W.Farndale,M.J.Barnes

Key ref:

J.Emsley et al. (2004). Structure of the integrin alpha2beta1-binding collagen peptide. J Mol Biol, 335, 1019-1028. PubMed id: 14698296 DOI: 10.1016/j.jmb.2003.11.030

Date:

18-Aug-03 Release date: 13-Jan-04

Protein chains

P02452  (CO1A1_HUMAN) -  Collagen alpha-1(I) chain

Seq: 1464 a.a.

Struc: 22 a.a.*

Protein chain

P02452  (CO1A1_HUMAN) -  Collagen alpha-1(I) chain

Seq: 1464 a.a.

Struc: 20 a.a.*

* PDB and UniProt seqs differ at 16 residue positions (black crosses)

DOI no: 10.1016/j.jmb.2003.11.030

J Mol Biol 335:1019-1028 (2004)

PubMed id: 14698296

Structure of the integrin alpha2beta1-binding collagen peptide.

J.Emsley, C.G.Knight, R.W.Farndale, M.J.Barnes.

ABSTRACT

We have determined the 1.8A crystal structure of a triple helical integrin-binding collagen peptide (IBP) with sequence (Gly-Pro-Hyp)(2)-Gly-Phe-Hyp-Gly-Glu-Arg-(Gly-Pro-Hyp)(3). The central GFOGER hexapeptide is recognised specifically by the integrins alpha2beta1, alpha1beta1, alpha10beta1 and alpha11beta1. These integrin/collagen interactions are implicated in a number of key physiological processes including cell adhesion, cell growth and differentiation, and pathological states such as thrombosis and tumour metastasis. Comparison of the IBP structure with the previously determined structure of an identical collagen peptide in complex with the integrin alpha2-I domain (IBP(c)) allows the first detailed examination of collagen in a bound and an unbound state. The IBP structure shows a direct and a water-mediated electrostatic interaction between Glu and Arg side-chains from adjacent strands, but no intra-strand interactions. The interactions between IBP Glu and Arg side-chains are disrupted upon integrin binding. A comparison of IBP and IBP(c) main-chain conformation reveals the flexible nature of the triple helix backbone in the imino-poor GFOGER region. This flexibility could be important to the integrin-collagen interaction and provides a possible explanation for the unique orientation of the three GFOGER strands observed in the integrin-IBP(c) complex crystal structure.

Selected figure(s)

Figure 1.
Figure 1. (a) Stereoview of the GFOGER triple helix showing the three zones. The three chains are strand 1 (grey), strand 2 (green) and strand 3 (blue). Glycine residues from strand 2 are labelled. The Figure was generated using MOLSCRIPT[27.] and Raster3D. [28.] (b) Two views of the IBP triple helix central zone at right-angles with interactions of the Glu and Arg side-chains illustrated. Hydrogen bonds appear as dotted lines and water molecules as red spheres.

Figure 3.
Figure 3. (a) Main-chain atoms from the superposed IBP (yellow) and IBPc (green) are shown with the three stands labelled. The peptides were superposed based on the C^a atom coordinates of residues GFOGER from the central zone (r.m.s.d. 0.754 Å). The line represents the axis through the average coordinates of C^a atoms from equivalent residues on each strand in the central zone. A similar axis is calculated for the N and C-terminal zones and these are used to calculate the angle of bends formed with the central zone. For the N and C-terminal zones these are 8.4° and 9.0° for IBP and 15.8° and 14.5° for IBPc. (b) A C^a backbone trace is shown for the IBP/IBPc superposed structures with the a2-I domain component of the complex also represented as a ribbon diagram (grey). The MIDAS metal ion is shown in blue and side-chains at the interface of the complex structure are shown in full with bonds indicated as dotted lines.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2004, 335, 1019-1028) copyright 2004.

Figures were selected by an automated process.