Identification of a DNA-contacting surface in the transcription factor sigma-54.
The transcription factor sigma-54 (sigma 54) is a sequence-specific DNA-binding protein that directs RNA polymerase to a particular class of promoter. The interaction of sigma 54 with promoter DNA has been analysed by protein-DNA crosslinking and enzymatic and chemical proteolysis. Direct physical evidence for a DNA-contacting surface within the carboxy-terminal one-third of the protein has been obtained. This region of sigma 54 is likely to be close to the surface of the protein, and contacts DNA when either sigma 54 or the sigma 54-holoenzyme bind specifically to promoter DNA. The amino-terminal region of sigma 54 appears to be highly susceptible to proteolysis, and its integrity influences the accessibility towards proteolysis of a second region of sigma 54, which includes the DNA-contacting surface. Thus the amino-terminal region of sigma 54 may have a role in influencing its DNA-binding properties, the major determinants of which appear to reside in the carboxy-terminal one-third of the protein.
Cannon
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W
Agricultural and Food Research Council, University of Sussex, Brighton, UK.
Claverie-Martin
F
F
Austin
S
S
Buck
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M
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D003432:Cross-Linking Reagents; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010449:Peptide Mapping; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D051877:RNA Polymerase Sigma 54; D012808:Sigma Factor / Q000737:chemistry / Q000378:metabolism*; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D012808:Sigma Factor; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54