Three-dimensional structure of gurmarin, a sweet taste-suppressing polypeptide.Arai, K., Ishima, R., Morikawa, S., Miyasaka, A., Imoto, T., Yoshimura, S., Aimoto, S., Akasaka, K.
(1995) J.Biomol.NMR 5: 297-305
- PubMed: 7787425
- PubMed Abstract:
- A Novel Peptide Isolated from the Leaves of Gymnema Sylvestre-I. Characterization and its Suppressive Effect on the Neural Responses to Sweet Taste Stimuli in the Rat
Imoto, T.,Miyasaka, A.,Ishima, R.,Akasaka, K.
(1991) COMP.BIOCHEM.PHYSIOL. A: PHYSIOL. 100: 309
- Amino Acid Sequence of Sweet-Taste-Suppressing Peptide (Gurmarin) from the Leaves of Gymnema Sylvestre
Kamei, K.,Takano, R.,Miyasaka, A.,Imoto, T.,Hara, S.
(1992) J.Biochem.(Tokyo) 111: 109
The solution structure of gurmarin was studied by two-dimensional proton NMR spectroscopy at 600 MHz. Gurmarin, a 35-amino acid residue polypeptide recently discovered in an Indian-originated tree Gymnema sylvestre, selectively suppresses the neural ...
The solution structure of gurmarin was studied by two-dimensional proton NMR spectroscopy at 600 MHz. Gurmarin, a 35-amino acid residue polypeptide recently discovered in an Indian-originated tree Gymnema sylvestre, selectively suppresses the neural responses of rat to sweet taste stimuli. Sequence-specific resonance assignments were obtained for all backbone protons and for most of the side-chain protons. The three-dimensional solution structure was determined by simulated-annealing calculations on the basis of 135 interproton distance constraints derived from NOEs, six distance constraints for three hydrogen bonds and 16 dihedral angle constraints derived from coupling constants. A total of 10 structures folded into a well-defined structure with a triple-stranded antiparallel beta-sheet. The average rmsd values between any two structures were 1.65 +/- 0.39 A for the backbone atoms (N, C alpha, C) and 2.95 +/- 0.27 A for all heavy atoms. The positions of the three disulfide bridges, which could not be determined chemically, were estimated to be Cys3-Cys18, Cys10-Cys23 and Cys17-Cys33 on the basis of the NMR distance constraints. This disulfide bridge pattern in gurmarin turned out to be analogous to that in omega-conotoxin and Momordica charantia trypsin inhibitor-II, and the topology of folding was the same as that in omega-conotoxin.
Department of Chemistry, Faculty of Science, Kyoto University, Japan.