Effects of conserved D/T loop substitutions in the pre-tRNA substrate on tRNase Z catalysis.
tRNAs are transcribed as precursors with a 5' end leader and a 3' end trailer. In the course of tRNA maturation, RNase P removes the 5' end leader and tRNase Z can endonucleolytically remove the 3' end trailer. A domain remote from the active site of tRNase Z recognizes and binds substrate, principally through contacts with the elbow (D/T loops) of the tRNA. To evaluate possible contacts, processing kinetics was performed using human nuclear encoded pre-tRNA(Arg) with substitutions in conserved D and T loop nucleotides. Changes in K(M) observed with some of the substitutions suggest contacts between tRNase Z and substrate tRNA in this region, and changes in tRNA structure provide an additional basis for interpretation of the kinetic effects.
Hopkinson
Angela
A
University of Michigan Department of Microbiology and Immunology, Ann Arbor, Michigan, USA.
Levinger
Louis
L
D001412:Bacillus subtilis / Q000201:enzymology; D001483:Base Sequence; D002384:Catalysis; D017124:Conserved Sequence; D004722:Endoribonucleases / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000737:chemistry* / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional; D012347:RNA, Transfer, Arg / Q000737:chemistry / Q000235:genetics; D012366:RNA, Transfer, Val / Q000737:chemistry / Q000235:genetics; D013379:Substrate Specificity
D012322:RNA Precursors; D012347:RNA, Transfer, Arg; D012366:RNA, Transfer, Val; D004722:Endoribonucleases; C531011:tRNase Z, human