Escherichia coli tRNase Z can shut down growth probably by removing amino acids from aminoacyl-tRNAs.
In most organisms, tRNase Z is considered to be essential for 3' processing of tRNA molecules. The Escherichia coli tRNase Z gene, however, appears to be dispensable under normal growth conditions, and its existence remained an enigma. Here we intensively examined various (pre-)tRNAs for good substrates of E. coli tRNase Z in vitro, and found that the enzyme can remove the 3' terminal CCA residues from mature tRNAs regardless of their nucleotide modifications. Furthermore, we discovered that E. coli tRNase Z, when sufficiently expressed in the cell, can shut down growth probably by removing amino acids from aminoacyl-tRNAs. We confirmed in vitro that E. coli tRNase Z exceptionally possesses the activity that cleaves off the 3' terminal residues charging an amino acid from an aminoacyl-tRNA molecule. The current data suggest that tRNase Z might help modulate a cell growth rate by repressing translation under some stressful conditions.
Takaku
Hiroaki
H
Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan.
Nashimoto
Masayuki
M
D000596:Amino Acids / Q000378:metabolism*; D001483:Base Sequence; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D013379:Substrate Specificity; D014158:Transcription, Genetic
D000596:Amino Acids; D029968:Escherichia coli Proteins; D012322:RNA Precursors; D012346:RNA, Transfer, Amino Acyl; D004722:Endoribonucleases; C534875:tRNase Z protein, E coli