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Your search keyword '"Sugawara, Taishi"' showing total 2 results
Start Over Author "Sugawara, Taishi" Publisher elsevier b.v.
2 results on '"Sugawara, Taishi"'

1. Bulky high-mannose-type N-glycan blocks the taste-modifying activity of miraculin

Author

Ito, Keisuke, Sugawara, Taishi, Koizumi, Ayako, Nakajima, Ken-Ichiro, Shimizu-Ibuka, Akiko, Shiroishi, Mitsunori, Asada, Hidetsugu, Yurugi-Kobayashi, Takami, Shimamura, Tatsuro, Asakura, Tomiko, Masuda, Katsuyoshi, Ishiguro, Masaji, Misaka, Takumi, Iwata, So, Kobayashi, Takuya, and Abe, Keiko

Subjects
Miraculin, Sweet protein, Taste, Yeast expression system, N-glycan, Steric hindrance
Abstract

BACKGROUND: Miraculin (MCL) is a taste-modifying protein that converts sourness into sweetness. The molecular mechanism underlying the taste-modifying action of MCL is unknown. METHODS: Here, a yeast expression system for MCL was constructed to accelerate analysis of its structure-function relationships. The Saccharomyces cerevisiae expression system has advantages as a high-throughput analysis system, but compared to other hosts it is characterized by a relatively low level of recombinant protein expression. To alleviate this weakness, in this study we optimized the codon usage and signal-sequence as the first step. Recombinant MCL (rMCL) was expressed and purified, and the sensory taste was analyzed. RESULTS: As a result, a 2 mg/l yield of rMCL was successfully obtained. Although sensory taste evaluation showed that rMCL was flat in taste under all the pH conditions employed, taste-modifying activity similar to that of native MCL was recovered after deglycosylation. Mutagenetic analysis revealed that the N-glycan attached to Asn42 was bulky in rMCL. CONCLUSIONS: The high-mannose-type N-glycan attached in yeast blocks the taste-modifying activity of rMCL. GENERAL SIGNIFICANCE: The bulky N-glycan attached to Asn42 may cause steric hindrance in the interaction between active residues and the sweet taste receptor hT1R2/hT1R3.

Published
2010

2. Characterization of the β-D-Glucopyranoside Binding Site of the Human Bitter Taste Receptor hTAS2R16.

Author

Sakurai, Takanobu, Misaka, Takumi, Ishiguro, Masaji, Masuda, Katsuyoshi, Sugawara, Taishi, Ito, Keisuke, Kobayashi, Takuya, Matsuo, Shinji, Ishimaru, Yoshiro, Asakura, Tomiko, and Abe, Keiko

Subjects
*BITTERNESS (Taste), *CELL receptors, *BINDING sites, *G proteins, *AMINO acids
Abstract

G-protein-coupled receptors mediate the senses of taste, smell, and vision in mammals. Humans recognize thousands of compounds as bitter, and this response is mediated by the hTAS2R family, which is one of the G-protein-coupled receptors composed of only 25 receptors. However, structural information on these receptors is limited. To address the molecular basis of bitter tastant discrimination by the hTAS2Rs, we performed ligand docking simulation and functional analysis using a series of point mutants of hTAS2R16 to identify its binding sites. The docking simulation predicted two candidate binding structures for a salicin-hTAS2R16 complex, and at least seven amino acid residues in transmembrane 3 (TM3), TM5, and TM6 were shown to be involved in ligand recognition. We also identified the probable salicin-hTAS2R16 binding mode using a mutated receptor experiment. This study characterizes the molecular interaction between hTAS2R16 and β-D-glucopyranoside and will also facilitate rational design of bitter blockers. [ABSTRACT FROM AUTHOR]

Published
2010
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