High-resolution solution structure of gurmarin, a sweet-taste-suppressing plant polypeptide

Fletcher, Jamie I., Dingley, Andrew J., Smith, Ross, Connor, Mark, Christie, MacDonald J. and King, Glenn F. (1999) High-resolution solution structure of gurmarin, a sweet-taste-suppressing plant polypeptide. European Journal of Biochemistry, 264 2: 525-533. doi:10.1046/j.1432-1327.1999.00659.x


Author Fletcher, Jamie I.
Dingley, Andrew J.
Smith, Ross
Connor, Mark
Christie, MacDonald J.
King, Glenn F.
Title High-resolution solution structure of gurmarin, a sweet-taste-suppressing plant polypeptide
Journal name European Journal of Biochemistry   Check publisher's open access policy
ISSN 0014-2956
Publication date 1999
Sub-type Article (original research)
DOI 10.1046/j.1432-1327.1999.00659.x
Volume 264
Issue 2
Start page 525
End page 533
Total pages 9
Place of publication Oxford
Publisher Blackwell Science
Collection year 1999
Language eng
Subject C1
270106 Cell Development (incl. Cell Division and Apoptosis)
780105 Biological sciences
Abstract 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 Å and 0.73 ± 0.09 Å, respectively. Gurmarin adopts a compact structure containing an antiparallel β-hairpin (residues 22–34), several well-defined β-turns, and a cystine-knot motif commonly observed in toxic and inhibitory polypeptides. Despite striking structural homology with δ-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.
Keyword gurmarin
ion channels
NMR
protein structure
sweet-taste suppression
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
 
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Created: Tue, 10 Jun 2008, 14:13:05 EST