Dubois Jean-Yves F, Kouwen Thijs R H M, Schurich Anna K C, Reis Carlos R, Ensing Hendrik T, Trip Erik N, Zweers Jessica C, van Dijl Jan Maarten
Department of Medical Microbiology, University Medical Center Groningen and University of Groningen, The Netherlands.
Antimicrob Agents Chemother. 2009 Feb;53(2):651-61. doi: 10.1128/AAC.01189-08. Epub 2008 Dec 1.
Bacillus subtilis strain 168 produces the extremely stable lantibiotic sublancin 168, which has a broad spectrum of bactericidal activity. Both sublancin 168 production and producer immunity are determined by the SPbeta prophage. While the sunA and sunT genes for sublancin 168 production have been known for several years, the genetic basis for sublancin 168 producer immunity has remained elusive. Therefore, the present studies were aimed at identifying an SPbeta gene(s) for sublancin 168 immunity. By systematic deletion analysis, we were able to pinpoint one gene, named yolF, as the sublancin 168 producer immunity gene. Growth inhibition assays performed using plates and liquid cultures revealed that YolF is both required and sufficient for sublancin 168 immunity even when heterologously produced in the sublancin-sensitive bacterium Staphylococcus aureus. Accordingly, we propose to rename yolF to sunI (for sublancin immunity). Subcellular localization studies indicate that the SunI protein is anchored to the membrane with a single N-terminal membrane-spanning domain that has an N(out)-C(in) topology. Thus, the bulk of the protein faces the cytoplasm of B. subtilis. This topology has not yet been reported for known bacteriocin producer immunity proteins, which implies that SunI belongs to a novel class of bacteriocin antagonists.
枯草芽孢杆菌168菌株产生极其稳定的羊毛硫抗生素sublancin 168，它具有广谱杀菌活性。sublancin 168的产生和生产者免疫均由SPbeta原噬菌体决定。虽然已知负责sublancin 168产生的sunA和sunT基因已有数年，但sublancin 168生产者免疫的遗传基础仍然不清楚。因此，本研究旨在鉴定负责sublancin 168免疫的SPbeta基因。通过系统缺失分析，我们能够确定一个名为yolF的基因作为sublancin 168生产者免疫基因。使用平板和液体培养物进行的生长抑制试验表明，即使在对sublancin敏感的金黄色葡萄球菌中异源表达时，YolF对于sublancin 168免疫也是必需且足够的。因此，我们建议将yolF重命名为sunI（用于sublancin免疫）。亚细胞定位研究表明，SunI蛋白通过单个N端跨膜结构域锚定在膜上，该结构域具有N（外）-C（内）拓扑结构。因此，该蛋白的大部分面向枯草芽孢杆菌的细胞质。已知的细菌素生产者免疫蛋白尚未报道这种拓扑结构，这意味着SunI属于一类新型的细菌素拮抗剂。
