Inhibitory effects of RraA and RraB on RNAse E-related enzymes imply conserved functions in the regulated enzymatic cleavage of RNA

• Published in: FEMS microbiology letters 2008-08, Vol.285 (1), p.10-15
• Main Authors: Yeom, Ji-Hyun, Go, Hayoung, Shin, Eunkyoung, Kim, Hyun-Lee, Han, Seung Hyun, Moore, Christopher J, Bae, Jeehyeon, Lee, Kangseok
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Catalysis; Degradation; degradosome; E coli; Endoribonucleases - antagonists & inhibitors; Endoribonucleases - genetics; Endoribonucleases - metabolism; Enzyme Inhibitors - metabolism; Enzymes; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; Genetics; Inhibitors; Kinases; Microbiology; Phosphorylase; Phosphorylases; Polynucleotide phosphorylase; Polyribonucleotide Nucleotidyltransferase - genetics; Polyribonucleotide Nucleotidyltransferase - metabolism; Protein Binding; Proteins; Regulators; Ribonuclease E; Ribonucleic acid; RNA; RNA Stability; RNA, Bacterial - genetics; RNA, Bacterial - metabolism; RNAse E; RNAse ES; RraA; RraB; Streptomyces coelicolor - enzymology; Streptomyces coelicolor - genetics; Substrates
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2008.01205.x

RraA and RraB are recently discovered protein inhibitors of RNAse E, which forms a large protein complex termed the degradosome that catalyzes the initial step in the decay and processing of numerous RNAs in Escherichia coli. Here, we report that these E. coli protein inhibitors physically interact with RNAse ES, a Streptomyces coelicolor functional ortholog of RNAse E, and inhibit its action in vivo as well as in vitro; however, unlike their ability to differentially modulate E. coli RNAse E action in a substrate-dependent manner by altering the composition of the degradosome, both proteins appear to have a general inhibitory effect on the ribonucleolytic activity of RNAse ES, which does not interact with E. coli polynucleotide phosphorylase, a major component of the degradosome. Our findings suggest that these regulators of RNAse activity have a conserved intrinsic property enabling them to directly act on RNAse E-related enzymes and inhibit their general ribonucleolytic activity.