Giacomini A, Squartini A, Nuti M P
Dipartimento di Biotecnologie Agrarie, University of Padova, via Romea 16, Legnaro (PD), I-35020, Italy.
Plasmid. 2000 Mar;43(2):111-22. doi: 10.1006/plas.1999.1447.
The complete sequence of the 19515-bp plasmid pMD136 from Pediococcus pentosaceus FBB61 (ATCC43200) has been determined. This plasmid is involved in Pediocin A production, a bacteriocin active against a wide range of gram-positive bacteria. It appears to replicate via a theta mechanism, with structures closely related to those of many lactococcal plasmids. Genes homologous to mobilization functions are also present, which are similar in sequence and arrangement to mobA, mobB, and mobC of some staphylococcal plasmids, although the last one contains a deletion in its central part. The region involved in bacteriocin activity has been limited to a 9.4-kb fragment, containing 10 open reading frames organized in a single operon. Since Pediocin A has a molecular weight of about 80 kDa (Piva and Headon, Microbiology, 140, 697-702, 1994), and a gene long enough to encode it is not present in pMD136, it is proposed that genes residing on the plasmid are responsible for the regulation of bacteriocinogenic activity. Gene arrangement and sequence homologies suggest the presence of a two-component-like regulatory mechanism.
已确定来自戊糖片球菌FBB61（ATCC43200）的19515碱基对质粒pMD136的完整序列。该质粒参与植物乳杆菌素A的产生，植物乳杆菌素是一种对多种革兰氏阳性菌有活性的细菌素。它似乎通过θ机制复制，其结构与许多乳球菌质粒的结构密切相关。也存在与移动功能同源的基因，这些基因在序列和排列上与一些葡萄球菌质粒的mobA、mobB和mobC相似，尽管最后一个基因在其中心部分有一个缺失。参与细菌素活性的区域已被限定为一个9.4kb的片段，其中包含10个以单个操纵子形式组织的开放阅读框。由于植物乳杆菌素A的分子量约为80kDa（Piva和Headon，《微生物学》，140，697 - 702，1994），且pMD136中不存在一个足够长以编码它的基因，因此有人提出质粒上的基因负责细菌素产生活性的调控。基因排列和序列同源性表明存在一种双组分样调控机制。
