[Purification and characterization of antifungal peptide LP-1].

An antifungal peptide LP-1 from Bacillus subtilis TG26 strain was purified by acid precipitation, acetone precipitation and Hi-pore reversed phase column chromatography. The molecular weight of LP-1 is 1057.3 D as determined by MALDI-TOF mass spectrometry, and its pI is 4.75 by PAG-IEF. It was also found to be thermostable. Its antifungal spectrum showed that LP-1 has strong inhibitory activity against many plant pathogenic fungi, such as Pythium aphanidermatum, Gibberella zeae, Alternaria longipe, Fusarium oxysporum f. lycopersici, etc.. The abnormal hyphal growth of Trichoderma viride caused by LP-1 such as swollen tips, twisted, short growth and cytoplasm condensation was also observed. Both ninhydrin reaction and peptide sequencing suggested that LP-1 is a cyclic peptide.