Purification and characterization of a novel antimicrobial peptide from Brevibacillus laterosporus strain A60

A novel antimicrobial peptide, with molecular mass of 1602.0469 Da, produced by Brevibacillus laterosporus strain A60 was isolated and purified from the soil of mango plants. The purification procedure consisted of ammonium sulfate precipitation, cation exchange chromatography on an HiTrap SP HP column, thin layer chromatography and High Performance Liquid Chromatography (HPLC) on C18 reversed-phase column. After the four isolation procedures, one peptide with antimicrobial activity was obtained and named BL-A60. The determination of the complete amino acid sequences of this peptide showed that it contains eleven amino acid residues, L-Y-K-L-V-K-V-V-L-N-M, and a choline connected to the N-terminal and a tenuazonic acid modified of the C-terminal. This peptide shows relatively low identification to other antimicrobial peptides from bacteria. Purified BL-A60 showed high pH and thermal stability and a strong inhibition of different stages of the life cycle of Phytophthora capsici, including mycelial growth, sporangia formation and cystospore germination, with EC50 values of 7.89, 0.60 and 21.96 μg ml−1, respectively.

► We purified a peptide, named BL-A60, from extracellular extract of Brevibacillus laterosporus. ► BL-A60 has a molecular weight of 1602.0469 Da. ► BL-A60 contains eleven amino acid residues and a choline connected to the N-terminal and a tenuazonic acid to the C-terminal. ► BL-A60 showed high pH and thermal stability. ► BL-A60 strongly inhibited different stages of the life cycle of Phytophthora capsici.