Exploration and functional analysis of a formaldehyde-driven glycine hydroxymethyltransferase

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07720
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied microbiology
• Research Institution: Osaka University
• Principal Investigator: HONDA Kohsuke 大阪大学, 生物工学国際交流センター, 教授 (90403162)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: グリシンヒドロキシメチル転移酵素 / スレオニンアルドラーゼ / Thermoplasma acidophilum

Outline of Final Research Achievements

In this study, reaction specificities of microbial glycine hydroxymethyltransferase (GHMT) was investigated to explore the diversity of microbial metabolisms of C1 compounds (e.g., methane, methanol, and formaldehyde) and their potential to be a novel biocatalytic tool for industrial utilization of C1 compounds. The enzyme derived from a thermophilic archaeon, Thermoplasma acidophilum, was shown to be able to use formaldehyde as a C1 donor for the hydroxymethylation of glyceine to serine in addition to its physiological substrate, methylene-THF. The enzyme also showed significant activity in the cleavage of threonine to glycine and acetaldehyde, suggesting that the enzyme is more related to the metabolism of threonine, rather than serine, in Thermoplasma acidophilum. This result shed a new light on a unique C1 metabolisms in archaea.

Free Research Field

応用微生物学

Academic Significance and Societal Importance of the Research Achievements

本研究は微生物におけるC1化合物（メタンなど）の代謝の多様性を解明することを目的に実施された。この結果、超好熱性アーキアの一種であるThermoplasma acidophilum由来酵素が、当初予想されたグリシンへのC1付加によるセリン生成に加え、C2付加によるスレオニン生産を効率的に触媒することを見出した。本成果は、真正細菌、真核生物とともに第3の生物ドメインを形成するアーキアのユニークな代謝反応の一端を示したものであり、微生物由来酵素が触媒する反応の多様性を示唆するものと位置づけられる。