1RO3

New structural insights on short disintegrin echistatin by NMR

Summary for 1RO3

• Entry DOI: 10.2210/pdb1ro3/pdb
• Related: 2ech
• Descriptor: Disintegrin echistatin (1 entity in total)
• Functional Keywords: no regular secondary structure, cell adhesion
• Biological source: Echis carinatus (saw-scaled viper)
• Cellular location: Secreted: P17347
• Total number of polymer chains: 1
• Total formula weight: 5435.19

Authors

Monleon, D.,Esteve, V.,Calvete, J.J.,Marcinkiewicz, C.,Celda, B. (deposition date: 2003-12-01, release date: 2003-12-09, Last modification date: 2024-11-13)

Primary citation

Monleon, D.,Esteve, V.,Kovacs, H.,Calvete, J.J.,Celda, B.
Conformation and concerted dynamics of the integrin-binding site and the C-terminal region of echistatin revealed by homonuclear NMR
Biochem.J., 387:57-66, 2005

PubMed Abstract: Echistatin is a potent antagonist of the integrins alpha(v)beta3, alpha5beta1 and alpha(IIb)beta3. Its full inhibitory activity depends on an RGD (Arg-Gly-Asp) motif expressed at the tip of the integrin-binding loop and on its C-terminal tail. Previous NMR structures of echistatin showed a poorly defined integrin-recognition sequence and an incomplete C-terminal tail, which left the molecular basis of the functional synergy between the RGD loop and the C-terminal region unresolved. We report a high-resolution structure of echistatin and an analysis of its internal motions by off-resonance ROESY (rotating-frame Overhauser enhancement spectroscopy). The full-length C-terminal polypeptide is visible as a beta-hairpin running parallel to the RGD loop and exposing at the tip residues Pro43, His44 and Lys45. The side chains of the amino acids of the RGD motif have well-defined conformations. The integrin-binding loop displays an overall movement with maximal amplitude of 30 degrees . Internal angular motions in the 100-300 ps timescale indicate increased flexibility for the backbone atoms at the base of the integrin-recognition loop. In addition, backbone atoms of the amino acids Ala23 (flanking the R24GD26 tripeptide) and Asp26 of the integrin-binding motif showed increased angular mobility, suggesting the existence of major and minor hinge effects at the base and the tip, respectively, of the RGD loop. A strong network of NOEs (nuclear Overhauser effects) between residues of the RGD loop and the C-terminal tail indicate concerted motions between these two functional regions. A full-length echistatin-alpha(v)beta3 docking model suggests that echistatin's C-terminal amino acids may contact alpha(v)-subunit residues and provides new insights to delineate structure-function correlations.

PubMed: 15535803
DOI: 10.1042/BJ20041343

Experimental method

SOLUTION NMR