Biomaterial Database

Alterations in the β flap and β' dock domains of the RNA polymerase abolish NusA-mediated feedback regulation of the metY-nusA-infB operon. 2011

Göran O Bylund, and Stefan Nord, and J Mattias Lövgren, and P Mikael Wikström

Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.

The RimM protein in Escherichia coli is important for the in vivo maturation of 30S ribosomal subunits and a ΔrimM mutant grows poorly due to assembly and translational defects. These deficiencies are suppressed partially by mutations that increase the synthesis of another assembly protein, RbfA, encoded by the metY-nusA-infB operon. Among these suppressors are mutations in nusA that impair the NusA-mediated negative-feedback regulation at internal intrinsic transcriptional terminators of the metY-nusA-infB operon. We describe here the isolation of two new mutations, one in rpoB and one in rpoC (encoding the β and β' subunits of the RNA polymerase, respectively), that increase the synthesis of RbfA by preventing NusA from stimulating termination at the internal intrinsic transcriptional terminators of the metY-nusA-infB operon. The rpoB2063 mutation changed the isoleucine in position 905 of the β flap-tip helix to a serine, while the rpoC2064 mutation duplicated positions 415 to 416 (valine-isoleucine) at the base of the β' dock domain. These findings support previously published in vitro results, which have suggested that the β flap-tip helix and β' dock domain at either side of the RNA exit tunnel mediate the binding to NusA during transcriptional pausing and termination.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009876	Operon	In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.	Operons
D010445	Peptide Elongation Factors	Protein factors uniquely required during the elongation phase of protein synthesis.	Elongation Factor,Elongation Factors, Peptide,Factor, Elongation,Factors, Peptide Elongation
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D012269	Ribosomal Proteins	Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.	Proteins, Ribosomal,Ribosomal Protein,Protein, Ribosomal
D012321	DNA-Directed RNA Polymerases	Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).	DNA-Dependent RNA Polymerases,RNA Polymerases,Transcriptases,DNA-Directed RNA Polymerase,RNA Polymerase,Transcriptase,DNA Dependent RNA Polymerases,DNA Directed RNA Polymerase,DNA Directed RNA Polymerases,Polymerase, DNA-Directed RNA,Polymerase, RNA,Polymerases, DNA-Dependent RNA,Polymerases, DNA-Directed RNA,Polymerases, RNA,RNA Polymerase, DNA-Directed,RNA Polymerases, DNA-Dependent,RNA Polymerases, DNA-Directed
D014157	Transcription Factors	Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.	Transcription Factor,Factor, Transcription,Factors, Transcription
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription
D015964	Gene Expression Regulation, Bacterial	Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.	Bacterial Gene Expression Regulation,Regulation of Gene Expression, Bacterial,Regulation, Gene Expression, Bacterial
D017434	Protein Structure, Tertiary	The level of protein structure in which combinations of secondary protein structures (ALPHA HELICES; BETA SHEETS; loop regions, and AMINO ACID MOTIFS) pack together to form folded shapes. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure.	Tertiary Protein Structure,Protein Structures, Tertiary,Tertiary Protein Structures