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Mycoplasma fermentans simplifies our vie ... ytic core of ribonuclease P RNA
Mycoplasma fermentans simplifies our view of the catalytic core of ribonuclease P RNA.
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The catalytic RNA moiety of (eu)bacterial RNase P is responsible for cleavage of the 5' leader sequence from precursor tRNAs. We report the sequence, the catalytic properties, and a phylogenetic-comparative structural analysis of the RNase P RNA from Mycoplasma fermentans, at 276 nt the smallest known RNase P RNA. This RNA is noteworthy in that it lacks a stem-loop structure (helix P12) that was thought previously to be universally present in bacterial RNase P RNAs. This finding suggests that helix P12 is not required for catalytic activity in vivo. In order to test this possibility in vitro, the kinetic properties of M. fermentans RNase P RNA and a mutant Escherichia coli RNase P RNA that was engineered to lack helix P12 were determined. These RNase P RNAs are catalytically active with efficiencies (Kcat/Km) comparable to that of native E. coli RNase P RNA. These results show that helix P12 is dispensable in vivo in some organisms, and therefore is unlikely to be essential for the mechanism of RNase P action. The notion that all phylogenetically volatile structures in RNase P RNA are dispensable for the catalytic mechanism was tested. A synthetic RNA representing the phylogenetic minimum RNase P RNA was constructed by deleting all evolutionarily variable structures from the M. fermentans RNA. This simplified RNA (Micro P RNA) was catalytically active in vitro with approximately 600-fold decrease in catalytic efficiency relative to the native RNA.
Siegel RW, Banta AB, Haas ES, Brown JW, Pace NR
RNA (New York, N.Y.)
1996-05-01 00:00
2
5
452-62
Base Sequence,Catalysis,Endoribonucleases,Escherichia coli Proteins,Kinetics,Molecular Sequence Data,Mycoplasma fermentans,Nucleic Acid Conformation,RNA, Bacterial,RNA, Catalytic,Ribonuclease P,Structure-Activity Relationship,Escherichia coli Proteins,RNA, Bacterial,RNA, Catalytic,Endoribonucleases,Ribonuclease P,ribonuclease P, E coli
Department of Biology, Indiana University, Bloomington, 47405, USA
RNA
NIGMS GM34527
1355-8382
951
True
8665412
