RNA polymerase mutants defective in the initiation of transcription-coupled DNA repair.
The bacterial Mfd protein is a transcription-repair coupling factor that performs two key functions during transcription-coupled DNA repair. The first is to remove RNA polymerase (RNAP) complexes that have been stalled by a DNA lesion from the site of damage, and the second is to mediate the recruitment of DNA repair proteins. Mfd also displaces transcription complexes that have been stalled by protein roadblocks, and catalyses the reactivation of transcription complexes that have become 'backtracked'. We have identified amino acid substitutions in the beta subunit of Escherichia coli RNAP that disrupt a direct interaction between Mfd and RNAP. These substitutions prevent Mfd displacing stalled RNAP from DNA in vivo and in vitro. They define a highly conserved surface-exposed patch on the beta1 domain of RNAP that is required by Mfd for the initial step of transcription-coupled repair, the enhancement of roadblock repression and the reactivation of backtracked transcription complexes.
Smith
A J
AJ
Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk Bristol BS8 1TD, UK.
Savery
N J
NJ
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000378:metabolism*; D004260:DNA Repair; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D014157:Transcription Factors; C072103:transcription repair coupling factor protein, Bacteria; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit