Regions of RNase E important for 5'-end-dependent RNA cleavage and autoregulated synthesis.
RNase E is an important regulatory enzyme that plays a key role in RNA processing and degradation in Escherichia coli. Internal cleavage by this endonuclease is accelerated by the presence of a monophosphate at the RNA 5' end. Here we show that the preference of E. coli RNase E for 5'-monophosphorylated substrates is an intrinsic property of the catalytically active amino-terminal half of the enzyme and does not require the carboxy-terminal region. This property is shared by the related E. coli ribonuclease CafA (RNase G) and by a cyanobacterial RNase E homolog derived from Synechocystis, indicating that the 5'-end dependence of RNase E is a general characteristic of members of this ribonuclease family, including those from evolutionarily distant species. Although it is dispensable for 5'-end-dependent RNA cleavage, the carboxy-terminal half of RNase E significantly enhances the ability of this ribonuclease to autoregulate its synthesis in E. coli. Despite similarities in amino acid sequence and substrate specificity, CafA is unable to replace RNase E in sustaining E. coli cell growth or in regulating RNase E production, even when overproduced sixfold relative to wild-type RNase E levels.
Jiang
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Skirball Institute of Biomolecular Medicine and Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA.
Diwa
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A
Belasco
J G
JG
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D000458:Cyanobacteria / Q000201:enzymology* / Q000235:genetics; D004722:Endoribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012313:RNA / Q000096:biosynthesis*; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012313:RNA; D004722:Endoribonucleases; C081905:rng protein, E coli; C022537:ribonuclease E