Analysis of the biosynthesis of antibacterial cyclic dipeptides in Nocardiopsis alba

• Published in: Archives of microbiology Vol. 196; no. 11; pp. 765 - 774
• Main Authors: Li, Yongli, Lai, Ying-Mi, Lu, Yi, Yang, Yu-Liang, Chen, Shawn
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.11.2014; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Actinomycetales - genetics; Actinomycetales - physiology; Agricultural biotechnology; Amino acids; Antibiotics; Antimicrobial Cationic Peptides - biosynthesis; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - isolation & purification; beta-glucuronidase; Biochemistry; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Cell Biology; Cloning; dipeptides; Dipeptides - biosynthesis; Dipeptides - genetics; Dipeptides - isolation & purification; Ecology; Enzymes; Fractionation; gene deletion; Gene expression; Gene Expression Regulation, Bacterial; genetic complementation; Genetic Complementation Test; Genome, Bacterial - genetics; Genomes; Invertebrates; Life Sciences; Liquid chromatography; Mass spectrometry; metabolic studies; Metabolites; Microbial Ecology; Microbiology; Microorganisms; multigene family; mutants; Nocardiopsis; Nocardiopsis alba; Original Paper; Osmoregulation; Peptides; plasmids; Plasmids - genetics; Sequence Deletion; transcription (genetics); Cyclic dipeptides; Genetic complementation; Reporter gene assay; Targeted gene deletion
• ISSN: 0302-8933; 1432-072X; 1432-072X
• DOI: 10.1007/s00203-014-1015-x

Nocardiopsis alba is frequently isolated from environment and has recently been suggested as a casual symbiotic actinobacterium of diverse invertebrates. Using activity-guided fractionation, we purified two antibacterial cyclic dipeptides, cyclo(ΔPhe–ΔLeu) (albonoursin) and cyclo(ΔmTyr–ΔLeu), from a culture of Nocardiopsis alba ATCC BAA-2165. Analysis of N. alba genome revealed genetic information similar to albonoursin biosynthetic gene cluster, albABC. An albABC gene deletion mutant of N. alba was generated. Liquid chromatography–mass spectrometry analysis showed that the mutant could not produce the cyclic dipeptides. Cyclic dipeptide production in the mutant was restored by genetic complementation with the albABC cloned in a native plasmid of Nocardiopsis. β-Glucuronidase reporter assays with a second mutant construct, in which albABC promoter is transcriptionally fused to the reporting gene gusA, indicated that albABC gene expression was subject to osmoregulation. The system presented will be used to study the metabolic and genetic control of cyclic dipeptide biosynthesis in Nocardiopsis.