Showing papers by "Murray P. Deutscher published in 2012"
TL;DR: It is shown here that only exponential phase RNase R is acetylated because the modifying enzyme, protein lysine acetyltransferase, Pka (YfiQ), is absent from late exponential and stationary phase cells, and newly synthesized RN enzyme R remains unmodified.
Abstract: RNase R is a processive exoribonuclease that plays an important role in degradation of structured RNAs in Escherichia coli. RNase R is unstable in exponential phase cells; however, under certain stress conditions, RNase R levels increase dramatically due to its stabilization. Binding of tmRNA and SmpB to the C-terminal region of RNase R is required for its instability, and this binding is regulated by acetylation of a single residue, Lys544, in exponential phase cells. RNase R is not acetylated in stationary phase. We show here that only exponential phase RNase R is acetylated because the modifying enzyme, protein lysine acetyltransferase, Pka (YfiQ), is absent from late exponential and stationary phase cells. As a consequence, newly synthesized RNase R remains unmodified. Together with the turnover of preexisting acetylated RNase R, no modified RNase R remains in stationary phase. We find that RNase R in cold-shocked cells also lacks the acetyl modification due to the absence of Pka. These data indicate that RNase R stability depends on Pka, which itself is regulated under stress conditions.
56 citations
TL;DR: A sequence of events, initiated by acetylation of a single Lys residue, results in proteolysis of RNase R in exponential phase cells, elucidates a novel regulatory mechanism previously unknown in bacteria.
34 citations
TL;DR: RsmJ is identified, the last unknown methyltransferase required for methylation of m(2)G1516 in 16S ribosomal RNA (rRNA), as the protein encoded by yhiQ, and the yhiZ gene is proposed to be renamed rsmJ.
28 citations
TL;DR: It is found that arsenate induces massive ribosome degradation, which provides a source of phosphate, and this results provide a simple explanation for the reported growth of GFAJ-1 in arsenate without invoking replacement of phosphorus by arsenic in biological macromolecules.
26 citations
TL;DR: How RNase BN can act as both an exo- and an endoribonuclease in vivo is explained and its exorib onuclease activity is demonstrated to be capable of functioning in vivo, thus widening the potential role of this enzyme in E. coli.
19 citations
TL;DR: The crystal structure and data indicate that DrII is the RNase II of D. radiodurans and that its structure and catalytic properties are distinct from those of other related enzymes.
8 citations