title: Acetylation regulates the stability of a bacterial protein: growth stage-dependent modification of RNase R.
abstract: RNase R, an Escherichia coli exoribonuclease important for degradation of structured RNAs, increases 3- to 10-fold under certain stress conditions, due to an increased half-life for this usually unstable protein. Components of the trans-translation machinery, tmRNA, and its associated protein, SmpB, are essential for RNase R instability. However, it is not understood why exponential phase RNase R is unstable or how it becomes stabilized in stationary phase. Here, we show that these phenomena are regulated by acetylation catalyzed by YfiQ protein. One residue, Lys544, is acetylated in exponential phase RNase R, but not in the stationary phase protein, resulting in tighter binding of tmRNA-SmpB to the C-terminal region of exponential phase RNase R and subsequent proteolytic degradation. Removal of the positive charge at Lys544 or a negative charge in the C-terminal region likely disrupts their interaction, facilitating tmRNA-SmpB binding. These findings indicate that acetylation can regulate the stability of a bacterial protein.
authors: Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33101, USA.
authors: Wenxing
authors: W
authors: Liang
authors: Arun
authors: A
authors: Malhotra
authors: Murray P
authors: MP
authors: Deutscher
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000378:metabolism; D005095:Exoribonucleases / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008239:Lysine / Q000737:chemistry; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D016601:RNA-Binding Proteins; C430328:small protein B; C096222:tmRNA; D000123:Acetyltransferases; C561243:acetyl-CoA synthetase acetylase, E coli; D005095:Exoribonucleases; C080868:ribonuclease R; D008239:Lysine