Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Eberhard Karls Universität Tübingen, Tübingen, Germany.
FEMS Microbiol Lett. 2012 Dec;337(2):81-8. doi: 10.1111/1574-6968.12031.
Antibiotic-producing soil bacteria of the genus Streptomyces form a huge natural reservoir of antibiotic resistance genes for the dissemination within the soil community. Streptomyces plasmids encode a unique conjugative DNA transfer system clearly distinguished from classical conjugation involving a single-stranded DNA molecule and a type IV protein secretion system. Only a single plasmid-encoded protein, TraB, is sufficient to translocate a double-stranded DNA molecule into the recipient in Streptomyces matings. TraB is a hexameric pore-forming ATPase that resembles the chromosome segregator protein FtsK and translocates DNA by recognizing specific 8-bp repeats present in the plasmid clt locus. Mobilization of chromosomal genes does not require integration of the plasmid, because TraB also recognizes clt-like sequences distributed all over the chromosome.
产生抗生素的土壤细菌链霉菌属形成了巨大的抗生素抗性基因天然库，可在土壤群落中传播。链霉菌质体编码一种独特的可移动性 DNA 转移系统，与涉及单链 DNA 分子和 IV 型蛋白分泌系统的经典接合明显不同。在链霉菌交配中，只有一个单一的质粒编码蛋白 TraB 就足以将双链 DNA 分子转移到受体中。TraB 是一种六聚体孔形成 ATP 酶，类似于染色体分离蛋白 FtsK，并通过识别质粒 clt 基因座中存在的特定 8 个碱基对重复序列来转位 DNA。染色体基因的动员不需要质粒的整合，因为 TraB 也识别分布在整个染色体上的 clt 样序列。
