Elucidation of salt-tolerant mechanism of glutaminase which alters its partial conformation by addition of NaCl

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07677
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied microbiology
• Research Institution: Nihon University
• Principal Investigator: YOSHIMUNE Kazuaki 日本大学, 生産工学部, 教授 (50325700)
• Research Collaborator: GOTO masaru
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 耐塩性酵素 / グルタミナーゼ

Outline of Final Research Achievements

Salt-tolerant glutaminase, which shows high activity even in the presence of 4.3 M NaCl, alters its conformation in response to salt concentration. On the contrary, salt-labile glutaminase which is inhibited in the presence of 1 M NaCl, does not change its conformation upon the addition of NaCl. Though their salt-tolerance differs, they share similar structure with superposition RMSD value 1.5 A. To reveal salt-tolerant mechanism of the salt-tolerant glutaminase, amino acid residue of the loop which alters its conformation of salt-tolerant glutaminase was substituted by site-directed mutagenesis. The mutant glutaminase showed decreased salt-tolerance. This fact suggests that the conformational change contribute the salt-tolerance of salt-tolerant glutaminase.

Free Research Field

酵素工学

Academic Significance and Societal Importance of the Research Achievements

酵素は室温で作用する副産物の少ない触媒であり、食品工業やファインケミカル業界で用いられている。一般的に酵素は高濃度の塩存在下で活性を失うため、食品に含まれる食塩や生産効率を上げるために高濃度に添加した基質によって活性を失ってしまう。このため一般的な酵素に高濃度の塩環境でも活性を失わない耐塩性を付与する技術は、酵素の新しい可能性を広げることが期待される。酵素の新しい耐塩化機構を提案する本研究の成果は酵素に耐塩性を付与する技術の開発に貢献する。