ABSTRACT
UNLABELLED: A novel antibacterial peptide specific to Streptococcus pyogenes was produced from dried fruit protein of Brucea javanica (L.) Merr. A mixture of active peptides from the fruit protein was produced in vitro by pepsin hydrolysis. The hydrolysate was purified by reverse-phase HPLC, and antimicrobial peptides active against Gram-negative and Gram-positive bacteria were analysed using SDS-PAGE and nanoLC-MS/MS. Here, four possible peptides were obtained and chemically synthesized for comparative study of the growth inhibition of Strep. pyogenes. One chemically synthesized peptide with a molecular mass of 1168.31 Da, His-Thr-Leu-Cys-Met-Asp-Gly-Gly-Ala-Thr-Tyr, showed the most potent antibacterial activity against Strep. pyogenes. This 11-amino acid peptide was named Brucin. Its bacterial inhibitory activity was 16-fold and 12.5-fold higher than penicillin G and chloramphenicol, respectively, with a MIC value of 20 µmol l(-1) . The results suggest that Brucin, a potent antibiotic peptide, may be developed as an alternative drug for the treatment of the disease caused by Strep. pyogenes. SIGNIFICANCE AND IMPACT OF THE STUDY: An antibacterial peptide, named Brucin with specificity for Streptococcus pyogenes, was produced in vitro from dried fruit protein of Brucea javanica (L.) Merr. by pepsin-catalysed hydrolysis. Its inhibitory activity towards the Gram-positive bacteria was higher than penicillin G and chloramphenicol. The result suggested that Brucin may be applied for the treatment of the disease caused by Strep. pyogenes(*) .
Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antimicrobial Cationic Peptides/pharmacology , Brucea/chemistry , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Plant Proteins/pharmacology , Amino Acid Sequence , Anti-Bacterial Agents/isolation & purification , Antimicrobial Cationic Peptides/chemistry , Antimicrobial Cationic Peptides/isolation & purification , Chloramphenicol/pharmacology , Electrophoresis, Polyacrylamide Gel , Fruit/chemistry , Microbial Sensitivity Tests , Molecular Sequence Data , Plant Proteins/chemistry , Plant Proteins/isolation & purification , Streptococcus pyogenes/drug effects , Tandem Mass SpectrometryABSTRACT
Two N-glycolylneuraminic acid-specific lectins, MLL 1 and 2, from leaves of Morus alba were studied for their anti-bacterial activity against P. syringae pv mori, which was a specific pathogenic bacterium of the mulberry leaf. MLL 1 but not MLL 2 was found to induce the agglutination of P. syringae pv mori. The MLL 1 can induce the agglutination only at the exponential phase of the bacterial growth in a liquid medium and the agglutination was specifically inhibited by N-glycolylneuraminic acid, N-acetylgalactosamine at 12.5 mM and bovine submaxillary mucin at 0.05 &mgr;g/ml.
