D-氨基酸在细菌生理中的结构性能和调节功能的研究进展

Roles of D-amino acids on the physiological structure and regulatory function of bacteria

摘要:

除最小的甘氨酸外，所有的氨基酸（amino acid，AA）都有手性，以D-氨基酸（DAA）或L-氨基酸（LAA）形式存在。DAA广泛存在于各类生物中，尤其是细菌。DAA虽没有参与蛋白质合成，但DAA尤其是非典型DAA在细菌生理中具有很多特殊功能。在结构性能方面，DAA是细菌细胞壁肽聚糖的重要组分，并参与组成某些非核糖体合成途径产生的生物多肽，少数细菌能产生含有D-Glu的γ-聚谷氨酸。对细胞个体而言，DAA能调节细菌表面电荷和自溶素活性，抑制细菌芽胞萌发，调节稳定期细胞壁的重塑及调节病原菌的毒力等。对细菌群落而言，DAA对生物膜的解聚和细菌生态也具有调控作用。此外，某些DAA还能直接作为营养支持某些细菌的生长，而有的DAA则具有抑菌作用。本文主要综述了DAA在细菌生理过程中发挥多项功能的研究进展。

Abstract:

All amino acids (AAs) other than glycine are chiral, existing in the forms of D-amino acids (DAAs) or L-amino acids (LAAs). Compared to widely studied LAAs, our knowledge about DAAs is still very limited. Herein, we review the advances in studying the physiological roles and functions of DAAs in bacteria. Though DAAs are not involved in protein synthesis, they are found in a wide range of organisms, especially bacteria. It is known that DAAs, especially non-canonical D-amino acids (NCDAAs), have a wide variety of special functions in bacterial physiology. As building blocks, DAAs are important components of peptidoglycan in bacterial cell wall, non-ribosomal peptides and poly-γ-glutamate. At the individual cell level, DAAs regulate bacterial surface charges and autolysin activity, inhibit the germination of bacterial spores, regulate cell wall remodeling during stationary phases and virulence of pathogenic bacteria. While at the population level, DAAs play important roles in biofilm development and bacterial ecology. Additionally, certain DAAs can support the growth of certain bacteria directly as nutrients, though some others act as inhibitors of bacterial growth.