Processing of histidine transfer RNA precursors. Abnormal cleavage site for RNase P.
The 5'-terminal guanylate residue (G-1) of mature Escherichia coli tRNA(His) is generated as a result of an unusual cleavage by RNase P (Orellana, O., Cooley, L., and Söll, D. (1986) Mol. Cell. Biol. 6, 525-529). We have examined the importance of the unique acceptor stem structure of E. coli tRNA(His) in determining the specificity of RNase P cleavage. Mutant tRNA(His) precursors bearing substitutions of the normal base G-1 or the opposing, potentially paired base, C73, can be cleaved at the +1 position, in contrast to wild-type precursors which are cut exclusively at the -1 position. These data indicate that the nature of the base at position -1 is of greater importance in determining the site of RNase P cleavage than potential base pairing between nucleotides -1 and 73. In addition, processing of the mutant precursors by M1-RNA or P RNA under conditions of ribozyme catalysis yields a higher proportion of +1-cleaved products in comparison to the reaction catalyzed by the RNase P holoenzyme. This lower sensitivity of the holoenzyme to alterations in acceptor stem structure suggests that the protein moiety of RNase P may play a role in determining the specificity of the reaction and implies that recognition of the substrate involves additional regions of the tRNA. We have also shown that the RNase P holoenzyme and tRNA(His) precursor of Saccharomyces cerevisiae, unlike their prokaryotic counterparts, do not possess these abilities to carry out this unusual reaction.
Burkard
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U
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511.
Willis
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Söll
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D
D004722:Endoribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D009154:Mutation; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000378:metabolism*; D012345:RNA, Transfer, Amino Acid-Specific / Q000096:biosynthesis*; D012354:RNA, Transfer, His / Q000096:biosynthesis*; D012362:RNA, Transfer, Ser / Q000096:biosynthesis; D043262:Ribonuclease P; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013329:Structure-Activity Relationship
D029968:Escherichia coli Proteins; D012322:RNA Precursors; D012345:RNA, Transfer, Amino Acid-Specific; D012354:RNA, Transfer, His; D012362:RNA, Transfer, Ser; D004722:Endoribonucleases; D043262:Ribonuclease P; C470865:ribonuclease P, E coli