1c4e
From Proteopedia
GURMARIN FROM GYMNEMA SYLVESTRE
Overview
Gurmarin is a 35-residue polypeptide from the Asclepiad vine Gymnema sylvestre. It has been utilised as a pharmacological tool in the study of sweet-taste transduction because of its ability to selectively inhibit the neural response to sweet tastants in rats. We have chemically synthesised and folded gurmarin and determined its three-dimensional solution structure to high resolution using two-dimensional NMR spectroscopy. Structure calculations utilised 612 interproton-distance, 19 dihedral-angle, and 18 hydrogen-bond restraints. The structure is well defined for residues 3-34, with backbone and heavy atom rms differences of 0.27 +/- 0.09 A and 0.73 +/- 0.09 A, respectively. Gurmarin adopts a compact structure containing an antiparallel beta-hairpin (residues 22-34), several well-defined beta-turns, and a cystine-knot motif commonly observed in toxic and inhibitory polypeptides. Despite striking structural homology with delta-atracotoxin, a spider neurotoxin known to slow the inactivation of voltage-gated Na+ channels, we show that gurmarin has no effect on a variety of voltage-sensitive channels.
About this Structure
1C4E is a Single protein structure of sequence from Gymnema sylvestre. This structure supersedes the now removed PDB entry 2gur. Full crystallographic information is available from OCA.
Reference
High-resolution solution structure of gurmarin, a sweet-taste-suppressing plant polypeptide., Fletcher JI, Dingley AJ, Smith R, Connor M, Christie MJ, King GF, Eur J Biochem. 1999 Sep;264(2):525-33. PMID:10491100 Page seeded by OCA on Fri May 2 12:19:01 2008
