2ech
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(New page: 200px<br /><applet load="2ech" size="450" color="white" frame="true" align="right" spinBox="true" caption="2ech" /> '''ECHISTATIN-THE REFINED STRUCTURE OF A DISINT...)
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ECHISTATIN-THE REFINED STRUCTURE OF A DISINTEGRIN IN SOLUTION BY 1H NMR
Overview
The structure of the disintegrin echistatin has been determined by 1H NMR, distance geometry calculations and restrained molecular dynamics, simulations. The structure has been refined from the preliminary distance, geometry calculations with the inclusion of additional 1H NMR data and, hydrogen bonds identified in early stages of the molecular dynamics, calculations. The calculations reported here allow a distinction to be, made between the two possible disulfide bridging patterns-echistatin is, crosslinked as follows: Cys2-Cys11, Cys7-Cys32, Cys8-Cys37, Cys20-Cys39., The final set of structures gives an average pairwise root mean square, distance of 0.100 nm (calculated over the backbone atoms of residues, Ser4-Cys20 and Asp30-Pro40). The core of echistatin is a well defined, though irregular structure, composed of a series of non-classical turns, crosslinked by the disulfide bridges and stabilised by hydrogen bonds. The, RGD sequence is located in a protruding loop whose stem is formed by two, rigid, hydrogen-bonded strands (Thr18-Cys20, Asp30-Cys32). The RGD, sequence is connected to this structure by short, flexible segments. High, (but not unlimited) mobility is probably necessary for fast recognition, and fitting to the integrin receptors. Sequence variability among the, disintegrins is found in the segments flanking the RGD sequence, suggesting that these may be important in conferring specificity for the, receptors.
About this Structure
2ECH is a Single protein structure of sequence from Echis carinatus with NH2 as ligand. Full crystallographic information is available from OCA.
Reference
Echistatin: the refined structure of a disintegrin in solution by 1H NMR and restrained molecular dynamics., Atkinson RA, Saudek V, Pelton JT, Int J Pept Protein Res. 1994 Jun;43(6):563-72. PMID:7928087
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