Identification of an operon and inducing peptide involved in the production of lactacin B by Lactobacillus acidophilus
Identification of an operon and inducing peptide involved in the production of lactacin B by Lactobacillus acidophilus
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DOI：
10.1111/j.1365-2672.2007.03417.x
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发表时间：
2007-11-01
影响因子：
4
通讯作者：
Klaenhammer, T. R.
中科院分区：
文献类型：
--
作者：
Dobson, A. E.;Sanozky-Dawes, R. B.;Klaenhammer, T. R.
目标：为了确定嗜酸乳杆菌NCFM基因组上的9.5 kb区域是否编码用于调节和产生乳酸菌素B（一种II类细菌素）的遗传决定因素，使用转录分析来鉴定疑似编码实验室操纵子的9.5 kb多顺反子区域。将12个推定的开放阅读框架（LBA 1803-LBA 1791）组织成三个簇：编码推定的双组分信号转导系统的生产和调节簇;编码推定的ABC转运蛋白的输出簇和由三种未知蛋白组成的最终簇。七个基因是典型的细菌素，编码小，阳离子肽，每个N-末端双甘氨酸前导基序。预测的ABC转运蛋白的失活完全消除了细菌素活性。当一起克隆和表达时，LBA 1803-LBA 1800导致乳酸菌素B活性的显著更高水平。这四种肽是化学合成的，但单独或组合时均未表现出细菌素活性。只有LBA 1800诱导的乳酸菌素B生产肉汤cultures.Conclusions：乳酸菌素B生产内的9.5 kb的12个基因，在一个单一的转录本中转录的实验室操纵子编码。LBA 1800是细菌素产生的诱导肽，研究的意义和影响：一个II类细菌素共有的三组分调节系统调节Lact产生这种细菌素。嗜酸乳杆菌
Aim: To determine if a 9.5-kb region on the Lactobacillus acidophilus NCFM genome, encoded the genetic determinants for regulation and production of lactacin B, a class II bacteriocin.Methods: Transcriptional analysis was used to identify a 9.5-kb polycistronic region suspected of encoding the lab operon. The 12 putative open reading frames (LBA1803-LBA1791) were organized into three clusters: a production and regulation cluster encoding a putative two-component signal transduction system; an export cluster encoding a putative ABC transporter and a final cluster composed of three unknown proteins. Seven genes were typical of bacteriocins, encoding small, cationic peptides, each with an N-terminal double-glycine leader motif. Inactivation of a predicted ABC transporter completely abolished bacteriocin activity. When cloned and expressed together, LBA1803-LBA1800 resulted in markedly higher levels of lactacin B activity. The four peptides were chemically synthesized but exhibited no bacteriocin activity, alone or in combination. Only LBA1800 induced lactacin B production in broth cultures.Conclusions: Lactacin B production is encoded within the 9.5-kb lab operon of 12 genes that are transcribed in a single transcript. LBA1800 is an inducing peptide of bacteriocin production.Significance and Impact of the Study: A three-component regulatory system common to class II bacteriocins regulates the production of this bacteriocin by Lact. acidophilus.