TtgV represses two different promoters by recognizing different sequences.

ABSTRACT: Expression of the multidrug efflux pump ttgDEF and ttgGHI operons is modulated in vivo mainly by the TtgV repressor. TtgV is a multidrug recognition repressor that exhibits a DNA binding domain with a long interaction helix comprising residues 47 to 64. The pattern of expression of the two pumps is different in Pseudomonas putida: in the absence of effectors, the promoter for the ttgD gene is silent, whereas the ttgG gene is expressed at a high basal level. This correlates with the fact that TtgV exhibits a higher affinity for the ttgD operator (K(D)=10+/-1 nM) than for the ttgG (K(D)=19+/-1 nM) operator. Sequence analysis revealed that both operators are 40% identical, and mutational analysis of the ttgD and ttgG operators combined with electrophoretic mobility shift assays and in vivo ex

SUBMITTER: Fillet S 

PROVIDER: S-EPMC2648374 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature