Snf2/Swi2-related ATPase Mot1 drives displacement of TATA-binding protein by gripping DNA.
Mot1 is a conserved Snf2/Swi2-related transcriptional regulator that uses ATP hydrolysis to displace TATA-binding protein (TBP) from DNA. Several models of the enzymatic mechanism have been proposed, including Mot1-catalyzed distortion of TBP structure, competition between Mot1 and DNA for the TBP DNA-binding surface, and ATP-driven translocation of Mot1 along DNA. ... Here, DNase I footprinting studies provide strong support for a 'DNA-based' mechanism of Mot1, which we propose involves ATP-driven DNA translocation. Mot1 forms an asymmetric complex with the TBP core domain (TBPc)-DNA complex, contacting DNA both upstream and within the major groove of the TATA Box. Contact with upstream DNA is required for Mot1-mediated displacement of TBPc from DNA. Using the SsoRad54-DNA complex as a model, DNA-binding residues in Mot1 were identified that are critical for Mot1-TBPc-DNA complex formation and catalytic activity, thus placing Mot1 mechanistically within the helicase superfamily. We also report a novel ATP-independent TBPc displacement activity for Mot1 and describe conformational heterogeneity in the Mot1 ATPase, which is likely a general feature of other enzymes in this class.
Mesh Terms:
Adenosine Triphosphatases, Adenosine Triphosphate, DNA, DNA Helicases, DNA-Binding Proteins, Models, Molecular, Protein Conformation, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, TATA-Binding Protein Associated Factors, TATA-Box Binding Protein, Transcription Factors
Adenosine Triphosphatases, Adenosine Triphosphate, DNA, DNA Helicases, DNA-Binding Proteins, Models, Molecular, Protein Conformation, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, TATA-Binding Protein Associated Factors, TATA-Box Binding Protein, Transcription Factors
EMBO J.
Date: Apr. 05, 2006
PubMed ID: 16541100
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