1C4E

GURMARIN FROM GYMNEMA SYLVESTRE

Replaces:  2GUR

Summary for 1C4E

• Entry DOI: 10.2210/pdb1c4e/pdb
• Related: 2GUR
• Descriptor: PROTEIN (GURMARIN) (1 entity in total)
• Functional Keywords: gurmarin, sweet taste suppression, cystine knot, sweet taste transduction, plant protein
• Biological source: Gymnema sylvestre
• Total number of polymer chains: 1
• Total formula weight: 4220.95

Authors

Fletcher, J.I.,Dingley, A.J.,King, G.F. (deposition date: 1999-07-27, release date: 1999-08-27, Last modification date: 2024-10-30)

Primary citation

Fletcher, J.I.,Dingley, A.J.,Smith, R.,Connor, M.,Christie, M.J.,King, G.F.
High-resolution solution structure of gurmarin, a sweet-taste-suppressing plant polypeptide.
Eur.J.Biochem., 264:525-533, 1999

PubMed 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 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.

PubMed: 10491100
DOI: 10.1046/j.1432-1327.1999.00659.x

Experimental method

SOLUTION NMR