Purification and characterization of antibacterial compounds of Pseudoalteromonas flavipulchra JG1

• Published in: Microbiology (Society for General Microbiology) 2012-03, Vol.158 (Pt 3), p.835-842
• Main Authors: MIN YU, JUNFENG WANG, KAIHAO TANG, XIAOCHONG SHI, SHUSHAN WANG, ZHU, Wei-Ming, ZHANG, Xiao-Hua
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - pharmacology; Bacteriology; Biological and medical sciences; Chromatography, Liquid; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Fundamental and applied biological sciences. Psychology; Magnetic Resonance Spectroscopy; Marinomonas mediterranea; Mass Spectrometry; Microbial Sensitivity Tests; Microbiology; Miscellaneous; Molecular Sequence Data; Molecular Weight; Pseudoalteromonas; Pseudoalteromonas - chemistry; Pseudoalteromonas tunicata; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Vibrio - drug effects; Vibrio - growth & development; Vibrio anguillarum
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.055970-0

Pseudoalteromonas flavipulchra JG1 produces a protein PfaP and a range of small-molecule compounds with inhibitory activities against Vibrio anguillarum. The PfaP protein was purified from the extracellular products of JG1 by electroelution, and antibacterial activity was observed by an in-gel antibacterial assay. The complete amino acid sequence (694 aa) of PfaP was determined by de novo peptide sequencing and subsequent alignment with the proteome sequence of strain JG1. The calculated molecular mass of PfaP was 77.0 kDa. PfaP was 58 % identical to l-lysine oxidase AlpP of Pseudoalteromonas tunicata D2, and 54 % identical to the marinocine antimicrobial protein of Marinomonas mediterranea MMB-1. Five small molecules (compounds 1-5) with antibacterial activity, which were identified as p-hydroxybenzoic acid (1), trans-cinnamic acid (2), 6-bromoindolyl-3-acetic acid (3), N-hydroxybenzoisoxazolone (4) and 2'-deoxyadenosine (5), were purified by sequential column chromatography over silica gel, Sephadex LH-20 and RP-18 from ethyl acetate extract of strain JG1, and their structures were determined by NMR and MS. Brown compound 3, the only brominated compound, showed antibacterial activity against both Gram-positive and Gram-negative bacteria.