Function analysis of diadenosine polyphosphate in myxobacterium

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07667
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied microbiology
• Research Institution: Kagawa University
• Principal Investigator: Kimura Yoshio 香川大学, 農学部, 教授 (10243750)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 粘液細菌 / ジアデノシンポリリン酸

Outline of Final Research Achievements

Myxococcus xanthus increased diadenosine polyphosphate (Ap4A and Ap5A) by several to five times under various stress conditions, but the amount of increase was smaller than that of E. coli. In this strain, ApnA was mainly synthesized by lysyl-tRNA synthetase and was mainly degraded by ApaH. The intracellular ApnA concentration of apaH deletion mutant was a 5-10-fold higher than that of wild-type strain, and the mutant reduced spore formation. Since Ap5A strongly inhibited adenylate kinase activity, energy homeostasis can not be maintained. Therefore, ApnA is sequentially degraded by the degrading enzyme in this bacterium and is maintained at a low concentration.

Free Research Field

微生物生理学

Academic Significance and Societal Importance of the Research Achievements

粘液細菌における種々のストレス条件下における細胞内ジアデノシンポリリン酸(ApnA)濃度の経時的変化とApnAの合成と分解に関わる主要な酵素を明らかにした。ApnA分解酵素欠損株では、細胞内のApnA濃度が5-10倍程度増加したが、種々のストレスに対して耐性にはならず、むしろ胞子形成の低下が見られた。
これらのことから、本菌はストレス条件下で生成されるApnAは本菌にとって有益に機能しないため、逐次分解しAMP、ADP及びATPにすることで特にAp5Aによるアデニル酸キナーゼの活性阻害を抑制し、エネルギーの恒常性を維持することで飢餓時での胞子形成を阻害させないようにしていることが示唆された。