8JZ8

Subatomic structure of orthorhombic thaumatin at 0.89 Angstroms

Summary for 8JZ8

• Entry DOI: 10.2210/pdb8jz8/pdb
• Descriptor: Thaumatin I, DI(HYDROXYETHYL)ETHER (3 entities in total)
• Functional Keywords: thaumatin, sweet-tasting protein, plant protein
• Biological source: Thaumatococcus daniellii
• Total number of polymer chains: 1
• Total formula weight: 22546.40

Authors

Masuda, T.,Suzuki, M.,Yamasaki, M.,Mikami, B. (deposition date: 2023-07-04, release date: 2024-05-15, Last modification date: 2024-10-30)

Primary citation

Masuda, T.,Suzuki, M.,Yamasaki, M.,Mikami, B.
Subatomic structure of orthorhombic thaumatin at 0.89 angstrom reveals that highly flexible conformations are crucial for thaumatin sweetness.
Biochem.Biophys.Res.Commun., 703:149601-149601, 2024

PubMed Abstract: Thaumatin is a sweet-tasting protein that elicits a sweet taste at a threshold of approximately 50 nM. Structure-sweetness relationships in thaumatin suggest that the basicity of two amino acids residues, Arg82 and Lys67, are particularly responsible for sweetness. Using tetragonal crystals, our structural analysis suggested that flexible sidechain conformations of these two residues play an important role in sweetness. However, in tetragonal crystals, Arg82 is adjacent to symmetry-related residues, and its flexibility is relatively restrained by the crystal packing. To reduce and diminish these symmetry-related effects, orthorhombic crystals were prepared, and their structures were successfully determined at a resolution of 0.89 Å. Within the orthorhombic lattice, two alternative conformations were more clearly visible at Lys67 than in a tetragonal system. Interestingly, for the first time, three alternative conformations at Arg82 were only found in an orthorhombic system. These results suggest the importance of flexible conformations in sweetness determinants. Such subtle structural variations might serve to adjust the complementarity of the electrostatic potentials of sweet receptors, thereby eliciting the potent sweet taste of thaumatin.

PubMed: 38364680
DOI: 10.1016/j.bbrc.2024.149601

Experimental method

X-RAY DIFFRACTION (0.89 Å)