Phosphorothioates in pre-tRNAs can change the specificities of RNAses P or reduce the cleavage efficiencies.
Several phosphorothioate-modified E coli and yeast pre-tRNAs were synthesized. If this modification included the phosphodiester at the RNase P cleavage site, two different effects were observed. With some pre-tRNAs the RNase P cleavage efficiency was severely reduced, whereas with other pre-tRNAs a new reaction type for RNase P was observed. Unlike the previously studied base or ribose modifications, phosphorothioates resulted in aberrant cleavages at unmodified phosphodiesters. These new sites could be located in the 5'-flank or in the acceptor stem of the tRNA domain. Modified mutants of E coli pre-tRNA(Tyr) with different base pairs at the RNase P cleavage site were cleaved with reduced efficiencies, but no aberrant products were observed.
Kahle
D
D
Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität, Kiel, Germany.
Küst
B
B
Krupp
G
G
D001482:Base Composition; D001483:Base Sequence; D004722:Endoribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016337:RNA, Catalytic / Q000378:metabolism*; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D043262:Ribonuclease P; D013872:Thionucleosides / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D015003:Yeasts / Q000235:genetics
D029968:Escherichia coli Proteins; D012322:RNA Precursors; D016337:RNA, Catalytic; D012346:RNA, Transfer, Amino Acyl; D013872:Thionucleosides; D012343:RNA, Transfer; D004722:Endoribonucleases; D043262:Ribonuclease P; C470865:ribonuclease P, E coli