Phosphorylation and DNA binding of the regulator DcuR of the fumarate-responsive two-component system DcuSR of Escherichia coli.
Microbiology (Reading)
; 150(Pt 4): 877-883, 2004 Apr.
Article
em En
| MEDLINE
| ID: mdl-15073297
ABSTRACT
The function of the response regulator DcuR of the DcuSR fumarate two-component sensory system of Escherichia coli was analysed in vitro. Isolated DcuR protein was phosphorylated by the sensory histidine kinase, DcuS, and ATP, or by acetyl phosphate. In gel retardation assays with target promoters (frdA, dcuB, dctA), phosphoryl DcuR (DcuR-P) formed a high-affinity complex, with an apparent K(D) (app. K(D)) of 0.2-0.3 microM DcuR-P, and a low-affinity (app. K(D) 0.8-2 microM) complex. The high-affinity complex was formed only with promoters transcriptionally-regulated by DcuSR, whereas low-affinity binding was seen also with some DcuSR-independent promoters. The binding site of DcuR-P at the dcuB promoter was determined by DNase I footprinting. One binding site of 42-52 nt (position -359 to -400/-410 nt upstream of the transcriptional start) was identified in the presence of low and high concentrations of DcuR-P. Non-phosphorylated DcuR, or DcuR-D56N mutated in the phosphoryl-accepting Asp56 residue, showed low-affinity binding to target promoters. DcuR-D56N was still able to interact with DcuS. DcuR-D56N increased the phosphorylation of DcuS and competitively inhibited phosphoryl transfer to wild-type DcuR.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fatores de Transcrição
/
DNA Bacteriano
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Regulação Bacteriana da Expressão Gênica
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Proteínas de Escherichia coli
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Proteínas de Ligação a DNA
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Escherichia coli
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Fumaratos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article