Basic Poly(amino acid) World: Quasi-ubiquitous Peptides for the Survival Strategy of Actinomycetes

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05798
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38020:Applied microbiology-related
• Research Institution: The University of Shiga Prefecture
• Principal Investigator: TAKEHARA Munenori 滋賀県立大学, 工学部, 講師 (30275169)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 塩基性ポリペプチド / ポリ(ε-L-リシン) / ポリ(γ-L-ジアミノ酪酸) / ポリ(γ-D-ジアミノ酪酸) / ポリ(L-ジアミノプロピオン酸) / 抗菌性 / 相乗作用 / 環境応答

Outline of Final Research Achievements

The author focused on a genus of microorganisms that “quasi-ubiquitously” produce basic polymers with antimicrobial properties, and aimed to evaluate and understand the biological significance of their production and function. Since basic polymers such as ε-PL, γ-PAB, and PAP are inductively biosynthesized only in an acidic environment, it is considered that they contribute to the maintenance of pH homeostasis of the producing cells. PAP, which has a novel “comb-like” structure and showed high antimicrobial activity against some yeast strains, had a property with a different antimicrobial range from that of ε-PL coproduced. Furthermore, the combined use of enantiomeric polymer of γ-PAB (γ-D-PAB) and ε-PL synergistically increased the antimicrobial activity against some yeasts and bacilli. On the other hand, these basic polymers could not play a role as metal ion scavenger.

Free Research Field

応用微生物学

Academic Significance and Societal Importance of the Research Achievements

「くし様」構造を有する天然の塩基性ポリマーに関する報告例はなく，今回の発見は，微生物が生産する塩基性ポリマーの多様性を顕在化しただけでなく，今後，生合成機構の解析へと研究展開していくうえでも重大な研究成果となった。以前に申請者らが見出したε-PL/γ-PAB併産菌と同様に，ε-PL/PAP併産菌も，異なるポリマーを共存させることで，より広範な抗菌作用を獲得してきたと考えられる。また，ε-PL/γ-D-PAB併用で相乗的な機能発現が認められたことから，塩基性ポリマーの多面的な抗菌作用機構の寄与が示唆された。このように，塩基性ポリマーを抗菌剤として効果的に利用するための指針となる知見が得られた。