Metal ion and substrate structure dependence of the processing of tRNA precursors by RNase P and M1 RNA.
A synthetic tRNA precursor analog containing the structural elements of Escherichia coli tRNA(Phe) was characterized as a substrate for E. coli ribonuclease P and for M1 RNA, the catalytic RNA subunit. Processing of the synthetic precursor exhibited a Mg2+ dependence quite similar to that of natural tRNA precursors such as E. coli tRNA(Tyr) precursor. It was found that Sr2+, Ca2+, and Ba2+ ions promoted processing of the dimeric precursor at Mg2+ concentrations otherwise insufficient to support processing; very similar behavior was noted for E. coli tRNA(Tyr). As noted previously for natural tRNA precursors, the absence of the 3'-terminal CA sequence in the synthetic precursor diminished the facility of processing of this substrate by RNase P and M1 RNA. A study of the Mg2+ dependence of processing of the synthetic tRNA dimeric substrate radiolabeled between C75 and A76 provided unequivocal evidence for an alteration in the actual site of processing by E. coli RNase P as a function of Mg2+ concentration. This property was subsequently demonstrated to obtain (Carter, B. J., Vold, B.S., and Hecht, S. M. (1990) J. Biol. Chem. 265, 7100-7103) for a mutant Bacillus subtilis tRNAHis precursor containing a potential A-C base pair at the end of the acceptor stem.
Surratt
C K
CK
Department of Chemistry, University of Virginia, Charlottesville 22901.
Carter
B J
BJ
Payne
R C
RC
Hecht
S M
SM
D001483:Base Sequence; D002413:Cations, Divalent; D004722:Endoribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012343:RNA, Transfer / Q000235:genetics* / Q000378:metabolism; D012365:RNA, Transfer, Tyr / Q000235:genetics / Q000378:metabolism; D043262:Ribonuclease P
D002413:Cations, Divalent; D029968:Escherichia coli Proteins; D012322:RNA Precursors; D012365:RNA, Transfer, Tyr; D012343:RNA, Transfer; D004722:Endoribonucleases; D043262:Ribonuclease P; C470865:ribonuclease P, E coli; D008274:Magnesium