Control of ColE1 plasmid replication. Intermediates in the binding of RNA I and RNA II.
Replication of plasmid ColE1 is regulated by a plasmid-specified small RNA (RNA I). RNA I binds to the precursor (RNA II) of the primer for DNA synthesis and inhibits primer formation. The process of binding of RNA I to RNA II that results in formation of a stably bound complex consists of a series of reactions forming complexes differing in the stability. Formation of a very unstable early intermediate that was previously inferred from the inhibition of stable binding caused by a second RNA I species was firmly established by more extensive studies. This complex is converted to a more stable yet reversible complex that was identified by its RNase sensitivity, which was altered from that of the earlier complex or from that of free RNA I or RNA II. In these complexes, most loops of RNA II interact with their complementary loops of RNA I. The kinetic and structural analyses of the binding process predict formation of a complex interacting at a single pair of complementary loops that precedes formation of these complexes. Thus the process of binding of RNA I to RNA II is seen to consist of a sequence of reactions producing a series of progressively more stable intermediates leading to the final product.
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
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D003086:Bacteriocin Plasmids; D001483:Base Sequence; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids; D012313:RNA / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D014158:Transcription, Genetic
D004269:DNA, Bacterial; C042027:RNA I; D012322:RNA Precursors; C034477:RNA primers; D012329:RNA, Bacterial; D012313:RNA; D012260:Ribonucleases