Department of Research and Development, Institut Rosell Inc., 6100 Avenue Royalmount, Montreal, Que., Canada.
Plasmid. 2010 Mar;63(2):108-17. doi: 10.1016/j.plasmid.2009.12.004. Epub 2010 Jan 4.
Lactobacillus helveticus R0052 is a bacterium used in commercial probiotic preparations. R0052 contains a small, cryptic plasmid comprised of eight open reading frames, four of which encode proteins of unknown function. Based on the sequence of the replication initiation protein RepA, pIR52-1 is a member of the recently described RepA_N family of Gram-positive theta-replicating plasmids. The repA gene of pIR52-1 is the minimal origin of replication for L. helveticus and other Lactobacillus hosts. Additionally, pIR52-1 belongs to a subgroup of the RepA_N plasmid family which have RepA proteins of high amino acid identity and a conserved, non-coding element upstream of repA which, in pIR52-1, is responsible for the control of plasmid copy number and contributes to plasmid maintenance.
瑞士乳杆菌 R0052 是一种用于商业益生菌制剂的细菌。R0052 含有一个小的、隐秘的质粒，由八个开放阅读框组成，其中四个编码未知功能的蛋白质。根据复制起始蛋白 RepA 的序列，pIR52-1 是最近描述的革兰氏阳性θ复制质粒 RepA_N 家族的成员。pIR52-1 的 repA 基因是瑞士乳杆菌和其他乳杆菌宿主的最小复制起点。此外，pIR52-1 属于 RepA_N 质粒家族的一个亚组，该亚组的 RepA 蛋白具有高度的氨基酸同一性，并且在 repA 上游有一个保守的非编码元件，在 pIR52-1 中，该元件负责控制质粒拷贝数并有助于质粒维持。
