| Autor: |
Fletcher JI; Department of Biochemistry, University of Sydney, Australia., Dingley AJ, Smith R, Connor M, Christie MJ, King GF |
| Jazyk: |
angličtina |
| Zdroj: |
European journal of biochemistry [Eur J Biochem] 1999 Sep; Vol. 264 (2), pp. 525-33. |
| DOI: |
10.1046/j.1432-1327.1999.00659.x |
| Abstrakt: |
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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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