5OLL

Crystal structure of gurmarin, a sweet taste suppressing polypeptide

Summary for 5OLL

• Entry DOI: 10.2210/pdb5oll/pdb
• Descriptor: Gurmarin, NICKEL (II) ION (3 entities in total)
• Functional Keywords: gurmarin, sweet, taste, knottin, gpcr, inhibitor, plant protein
• Biological source: Gymnema sylvestre (Gurmar)
• Total number of polymer chains: 1
• Total formula weight: 4415.05

Authors

Sigoillot, M.,Neiers, F.,Legrand, P.,Roblin, P.,Briand, L. (deposition date: 2017-07-28, release date: 2018-08-08, Last modification date: 2019-02-20)

Primary citation

Sigoillot, M.,Brockhoff, A.,Neiers, F.,Poirier, N.,Belloir, C.,Legrand, P.,Charron, C.,Roblin, P.,Meyerhof, W.,Briand, L.
The Crystal Structure of Gurmarin, a Sweet Taste-Suppressing Protein: Identification of the Amino Acid Residues Essential for Inhibition.
Chem. Senses, 43:635-643, 2018

PubMed Abstract: Gurmarin is a highly specific sweet taste-suppressing protein in rodents that is isolated from the Indian plant Gymnema sylvestre. Gurmarin consists of 35 amino acid residues containing 3 intramolecular disulfide bridges that form a cystine knot. Here, we report the crystal structure of gurmarin at a 1.45 Å resolution and compare it with previously reported nuclear magnetic resonance solution structures. The atomic structure at this resolution allowed us to identify a very flexible region consisting of hydrophobic residues. Some of these amino acid residues had been identified as a putative binding site for the rat sweet taste receptor in a previous study. By combining alanine-scanning mutagenesis of the gurmarin molecule and a functional cell-based receptor assay, we confirmed that some single point mutations in these positions drastically affect sweet taste receptor inhibition by gurmarin.

PubMed: 30137256
DOI: 10.1093/chemse/bjy054

Experimental method

X-RAY DIFFRACTION (1.45 Å)