Amortegui Jairo, Rodríguez-López Alexander, Rodríguez Deicy, Carrascal Ana K, Alméciga-Díaz Carlos J, Melendez Adelina del P, Sánchez Oscar F
Institute for the Study of Inborn Errors of Metabolism, School of Sciences, Pontificia Universidad Javeriana, Bogotá, Colombia.
Appl Biochem Biotechnol. 2014 Apr;172(7):3374-89. doi: 10.1007/s12010-014-0757-x. Epub 2014 Feb 15.
Bacteriocins are low molecular peptides with antimicrobial activity, which are of great interest as food bio-preservatives and for treating diseases caused by pathogenic bacteria. In this study, we present the characterization of bacteriocins produced by Lactobacillus plantarum LE5 and LE27 isolated from ensiled corn. Bacteriocins were purified through ammonium sulfate precipitation and double dialysis by using 12- and 1-kDa membranes. Bacteriocins showed activity against Listeria innocua, Listeria monocytogenes, and Enteroccocus faecalis. Molecular weight was estimated through Tricine-SDS-PAGE and overloading the gel onto Mueller-Hinton agar seeded with L. monocytogenes, showing an inhibition zone between 5 and 10 kDa. NanoLC-MS/MS analysis allowed the identification of UPF0291 protein (UniProtKB/Swiss-Prot Q88VI7), which is also presented in other lactic acid bacteria without assigned function. Ab initio modeling showed it has an α-helix-rich structure and a large positive-charged region. Bacteriocins were stable between 4 and 121 °C and pH 2 and 12, and the activity was inhibited by SDS and proteases. Mode of action assay suggests that the bacteriocin causes of target microorganism. Taken together, these results describe a possible new class IIa bacteriocin produced by L. plantarum, which has a wide stability to physicochemical conditions, and that could be used as an alternative for the control of foodborne diseases.
细菌素是具有抗菌活性的低分子肽，作为食品生物防腐剂和治疗由病原菌引起的疾病具有很大的应用价值。在本研究中，我们对从青贮玉米中分离出的植物乳杆菌LE5和LE27产生的细菌素进行了表征。通过硫酸铵沉淀和使用12 kDa和1 kDa膜进行双重透析来纯化细菌素。细菌素对无害李斯特菌、单核细胞增生李斯特菌和粪肠球菌具有活性。通过Tricine-SDS-PAGE并将凝胶过载到接种有单核细胞增生李斯特菌的穆勒-欣顿琼脂上估计分子量，显示抑菌圈在5至10 kDa之间。纳米液相色谱-串联质谱分析鉴定出UPF0291蛋白（UniProtKB/Swiss-Prot Q88VI7），该蛋白在其他未赋予功能的乳酸菌中也有发现。从头建模显示它具有富含α-螺旋的结构和一个大的带正电荷区域。细菌素在4至121°C以及pH 2至12之间稳定，并且其活性受到SDS和蛋白酶的抑制。作用方式分析表明该细菌素可导致靶标微生物死亡。综上所述，这些结果描述了一种可能由植物乳杆菌产生的新型IIa类细菌素，它对理化条件具有广泛的稳定性，并且可作为控制食源性疾病的一种替代物。
