Tahara T, Kanatani K
Research Laboratory, Tamon Sake Brewing Co. Ltd, Hyogo, Japan.
J Appl Bacteriol. 1996 Dec;81(6):669-77. doi: 10.1111/j.1365-2672.1996.tb03563.x.
Lactobacillus acidophilus JCM 1229 produces a heat-stable bacteriocin, designated as acidocin J1229, that has a narrow inhibitory spectrum. Production of acidocin J1229 in MRS broth was pH dependent, with maximum activity detected in broth culture maintained at pH 5.0. Acidocin J1229 was purified by ammonium sulphate precipitation and sequential cation exchange and reversed-phase chromatographies. The sequence of the first 24 amino acid residues of the N terminus of acidocin J1229 was determined. The molecular mass of acidocin J1229 as determined by mass spectrometry was 6301 Da. Acidocin J1229 showed a bactericidal effect but not a bacteriolytic effect on sensitive cells. Acidocin J1229 dissipated the membrane potential and the pH gradient in sensitive cells, which affected such proton motive force-dependent processes as amino acid transport. Acidocin J1229 also caused an efflux of glutamate, previously taken up via a unidirectional ATP-driven transport system. Secondary structure prediction revealed the presence of an amphiphilic alpha-helix region that could form hydrophilic pores. These results suggest that acidocin J1229 is a pore-forming peptide that creates cell membrane channels through the "barrel-stave' mechanism.
嗜酸乳杆菌JCM 1229产生一种热稳定的细菌素，命名为嗜酸菌素J1229，其抑菌谱较窄。在MRS肉汤中嗜酸菌素J1229的产生依赖于pH值，在pH 5.0的肉汤培养物中检测到最大活性。嗜酸菌素J1229通过硫酸铵沉淀以及连续的阳离子交换和反相色谱法进行纯化。测定了嗜酸菌素J1229 N端前24个氨基酸残基的序列。通过质谱测定，嗜酸菌素J1229的分子量为6301 Da。嗜酸菌素J1229对敏感细胞表现出杀菌作用而非溶菌作用。嗜酸菌素J1229使敏感细胞的膜电位和pH梯度消失，这影响了诸如氨基酸转运等依赖质子动力的过程。嗜酸菌素J1229还导致先前通过单向ATP驱动转运系统摄取的谷氨酸外流。二级结构预测显示存在一个可形成亲水孔的两亲性α-螺旋区域。这些结果表明，嗜酸菌素J1229是一种通过“桶板”机制形成细胞膜通道的成孔肽。
