The nucleic acid melting activity of Escherichia coli CspE is critical for transcription antitermination and cold acclimation of cells.
Members of bacterial Csp (cold-shock protein) family promote cellular adaptation to low temperature and participate in many other aspects of gene expression regulation through mechanisms that are not yet fully elucidated. Csp proteins interact with single-stranded nucleic acids and destabilize nucleic acid secondary structures. Some Csp proteins also act as transcription antiterminators in vivo and in vitro. Here, we selected a mutation in the cloned cspE gene that abolished CspE-induced transcription antitermination. In vitro, mutant CspE showed RNA binding activity similar to that of the wild-type CspE but was unable to destabilize nucleic acid secondary structures. Thus, nucleic acid melting ability of CspE and its transcription antitermination activity are correlated. In vivo, mutant cspE was functional with respect to up-regulation of expression of rpoS, but, unlike the wild-type cspE, it did not complement the cold-sensitive phenotype of the quadruple DeltacspADeltacspBDeltacspGDeltacspE deletion strain. Thus, the nucleic acid-melting activity of Csp is critical for its prototypical function of supporting low temperature survival of the cell.
Phadtare
Sangita
S
Department of Biochemistry, Robert Wood Johnson Medical School, Rutgers, State University of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA.
Inouye
Masayori
M
Severinov
Konstantin
K
D001120:Arginine / Q000737:chemistry; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry; D015153:Blotting, Western; D002942:Circular Dichroism; D003001:Cloning, Molecular; D003080:Cold Temperature; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D006360:Heat-Shock Proteins / Q000378:metabolism / Q000502:physiology*; D006639:Histidine / Q000737:chemistry; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009690:Nucleic Acid Conformation; D010641:Phenotype; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012313:RNA / Q000378:metabolism; D012808:Sigma Factor / Q000096:biosynthesis / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D014158:Transcription, Genetic
D001426:Bacterial Proteins; C088097:CspE protein, E coli; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D006639:Histidine; D012313:RNA; D001120:Arginine