Mechanism of autonomous control of the Escherichia coli F plasmid: different complexes of the initiator/repressor protein are bound to its operator and to an F plasmid replication origin.
Mechanism of autonomous control of the Escherichia coli F plasmid: different complexes of the initiator/repressor protein are bound to its operator and to an F plasmid replication origin.
复制标题
大肠杆菌 F 质粒的自主控制机制：启动子/阻遏蛋白的不同复合物与其操纵子和 F 质粒复制起点结合。
DOI：
10.1093/nar/14.14.5693
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发表时间：
1986
影响因子：
14.9
通讯作者：
Ray,DS
中科院分区：
文献类型：
--
作者：
Masson,L;Ray,DS
E蛋白是F质粒repE基因的29kd产物，在F复制的自动调节中起着积极和消极的作用。我们已经克隆了repE基因并在诱导型ATG融合载体中表达，并且已经检测到E蛋白与repE操纵子和F质粒复制起点ori2内的四个19碱基对直接重复序列（incB）的特异性结合，E蛋白在repE操纵子处的结合以比ori2处更高的亲和力发生（incB），并且对至少30个碱基对提供几乎完全的保护，而E蛋白与ori2区域中的同向重复序列的结合显示出对DNA酶切割的敏感性增强和降低的交替模式，这与蛋白质诱导的DNA折叠一致。这些结果为F质粒复制的模型提供了直接的生物力学支持，其中E蛋白既作为复制的启动子又作为自身合成的自阻遏物。
E protein, the 29 kd product of the F plasmid repE gene, plays both positive and negative roles in the autoregulation of F replication. We have cloned and expressed the repE gene in an inducible ATG-fusion vector and have detected specific binding of E protein to the repE operator and to four 19-base pair direct repeats (incB) within the F plasmid replication origin ori2 Binding of E protein at the repE operator occurs with higher affinity than at ori2(incB) and gives almost complete protection to at least 30 base pairs, whereas binding of E protein to the direct repeats in the ori2 region shows an alternating pattern of enhanced and reduced sensitivity to DNAase cleavage consistent with a protein-induced folding of the DNA. These results provide direct biochanical support for a model of F plasmid replication in which the E protein serves both as an initiator of replication and as an autorepressor of its own synthesis.