Escherichia coli topoisomerase III-catalyzed cleavage of RNA.
Relaxation of superhelical DNA by Escherichia coli topoisomerase III (Topo III) was inhibited by the inclusion of tRNA in the reaction mixture. Investigation of the basis of this inhibition revealed that Topo III could bind RNA and establish a cleavage-religation equilibrium. The addition of SDS to these reaction mixtures induced cleavage of the RNA by Topo III. The nucleotide sequences of RNA and DNA cleavage sites were identical, although cleavage site preference differed. Thus, the possibility that Topo III can pass strands of RNA as well as strands of DNA must be considered in accounting for the role of this enzyme in nucleic acid metabolism.
DiGate
R J
RJ
Program in Molecular Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Marians
K J
KJ
D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D009843:Oligoribonucleotides / Q000378:metabolism; D012313:RNA / Q000096:biosynthesis / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D013379:Substrate Specificity
D009838:Oligodeoxyribonucleotides; D009843:Oligoribonucleotides; D012965:Sodium Chloride; D012313:RNA; D004247:DNA; D004264:DNA Topoisomerases, Type I