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.
Tomizawa
J
J
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
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