A thermostable platform for transcriptional regulation: the DNA-binding properties of two Lrp homologs from the hyperthermophilic archaeon Methanococcus jannaschii.
The hyperthermophilic archaeon Methanococcus jannaschii encodes two putative transcription regulators, Ptr1 and Ptr2, related to the bacterial Lrp/AsnC family of transcriptional regulators. We show that these two small helix-turn-helix proteins are specific DNA-binding proteins recognizing sites in their respective promoter regions. In vitro selection at high temperature has been used to isolate sets of high- affinity DNA sites that define a palindromic consensus binding sequence for each protein. Ptr1 and Ptr2 bind these cognate sites from one side of the DNA helix, as dimers, with each protein monomer making base- specific contacts in the major groove. As the first archaeal DNA-binding proteins with clearly defined specificities, Ptr1 and Ptr2 provide a thermostable DNA-binding platform for analysis of effector interactions with the core archaeal transcription apparatus; a platform allowing manipulation of promoter structure and examination of mechanisms of action at heterologous promoters.
Ouhammouch
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Division of Biology and Center for Molecular Genetics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0634, USA. mouham@biomail.ucsd.edu
Geiduschek
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EP
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D019848:Gene Expression Regulation, Archaeal; D019077:Helix-Turn-Helix Motifs; D006358:Hot Temperature; D051756:Leucine-Responsive Regulatory Protein; D017017:Methanococcus / Q000235:genetics*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014158:Transcription, Genetic
D019843:Archaeal Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; C423031:Ptr1 protein, Methanococcus jannaschii; C423032:Ptr2 protein, Methanococcus jannaschii; D011994:Recombinant Proteins; D014157:Transcription Factors; D051756:Leucine-Responsive Regulatory Protein