侧孢短芽孢杆菌抗菌肽的结构与性质

为了研究侧孢短芽孢杆菌S62-9所产抗菌肽的结构与性质，采用MALDI-TOF/TOF、FT-IR对抗菌肽的相对分子质量、氨基酸序列及二级结构进行解析。结果显示，该抗菌肽的相对分子质量为1 602.004 4 Da，由11个氨基酸组成：L-Y-K-L-V-K-V-V-L-N-M，其N端有一分子胆碱修饰，C端有细交链孢菌酮酸衍生物修饰，二级结构主要由β-转角和规卷曲构成。抑菌试验结果显示：抗菌肽对所选4株革兰氏阳性菌的MIC为7.81 μg/mL，对4株革兰氏阴性菌的MIC为7.81~62.5 μg/mL，对青霉、黑曲霉的MIC分别为31.25、62.5 μg/mL。溶血试验结果显示：抗菌肽质量浓度≤62.5 μg/mL时，其溶血率不超过10%；但抗菌肽质量浓度≥125 μg/mL时，其溶血率超过80%。稳定性实验结果显示：该抗菌肽具有很强的热稳定性和pH稳定性，对蛋白酶有很好的耐受性。
In order to study the structure and function of antimicrobial peptide from Brevibacillus laterosporus S62-9，the molecular mass，amino acid sequence and secondary structure of antimicrobial peptide were analyzed by MALDI-TOF/TOF mass spectrometry and FT-IR. The results indicated that the molecular mass of the peptide is 1 602.004 4 Da，and the primary structure of the peptide contains eleven amino acid residues，L-Y-K-L-V-K-V-V-L-N-M with a choline and a tenuazonic acid connected to the N-terminal and the C-terminal， respectively. The secondary structure mainly consists of β-turn and random coil. Antimicrobial assay indicated that the peptide is able to inhibit the growth both Gram-positive and Gram-negative bacteria with the MIC values of 7.81 μg/mL and 7.81~62.5 μg/mL respectively. The peptide also can inhibit the growth of the Penicillium sp and Aspergillus niger with the MIC value of 31.25 μg/mL and 62.5 μg/mL，repectively. The hemolytic results showed that the peptide exhibited hemolytic activity below 10% at 62.5 μg/mL，and more than 80% at 125 μg/mL. In addition，the peptide showed high thermal and pH stability and a strong resisted proteinases