PMID:15507429
| Citation |
Lacour, S, Leroy, O, Kolb, A and Landini, P (2004) Substitutions in region 2.4 of sigma70 allow recognition of the sigmaS-dependent aidB promoter. J. Biol. Chem. 279:55255-61 |
|---|---|
| Abstract |
The strict dependence of transcription from the aidB promoter (PaidB) on the Esigma(S) form of RNA polymerase is because of the presence of a C nucleotide as the first residue of the -10 promoter sequence (-12C), which does not allow an open complex formation by Esigma(70). In this report, sigma(70) mutants carrying either the Q437H or the T440I single amino acid substitutions, which allow -12C recognition by sigma(70), were tested for their ability to carry out transcription from PaidB. The Gln-437 and Thr-440 residues are located in region 2.4 of sigma(70) and correspond to Gln-152 and Glu-155 in sigma(S). Interestingly, the Q437H mutant of sigma(70), but not T440I, was able to promote an open complex formation and to initiate transcription at PaidB. In contrast to T440I, a T440E mutant was proficient in carrying out transcription from PaidB. No sigma(70) mutant displayed significantly increased interaction with a PaidB mutant in which the -12C was substituted by a T (PaidB((C12T))), which is also efficiently recognized by wild type sigma(70). The effect of the T440E mutation suggests that the corresponding Glu-155 residue in sigma(S) might be involved in -12C recognition. However, substitution to alanine of the Glu-155 residue, as well as of Gln-152, in the sigma(S) protein did not significantly affect Esigma(S) interaction with PaidB. Our results reiterate the importance of the -12C residue for sigma(S)-specific promoter recognition and strongly suggest that interaction with the -10 sequence and open complex formation are carried out by different determinants in the two sigma factors. |
| Links |
PubMed Online version:10.1074/jbc.M410855200 |
| Keywords |
Binding, Competitive; DNA/chemistry; DNA-Directed RNA Polymerases/chemistry; DNA-Directed RNA Polymerases/metabolism; Deoxyribonuclease I/chemistry; Dose-Response Relationship, Drug; Escherichia coli Proteins/genetics; Genetic Vectors; Glutamic Acid/chemistry; Glutamine/chemistry; Heparin/chemistry; Mutation; Plasmids/metabolism; Potassium Permanganate/chemistry; Promoter Regions, Genetic; Protein Binding; Sigma Factor/chemistry; Sigma Factor/metabolism; Threonine/chemistry; Transcription, Genetic |
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