1qp9
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(New page: 200px<br /><applet load="1qp9" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qp9, resolution 2.8Å" /> '''STRUCTURE OF HAP1-PC7...)
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Revision as of 22:44, 20 November 2007
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STRUCTURE OF HAP1-PC7 COMPLEXED TO THE UAS OF CYC7
Overview
HAP1 is a transcription factor in yeast whose DNA-binding domain has been, implicated in directly affecting transcriptional activation. Two separate, mutations in the DNA-binding domain, S63G (HAP1-PC7) and S63R (HAP1-18), retain wild-type binding affinity. However, HAP1-PC7 is transcriptionally, silent while HAP1-18 shows highly elevated levels of transcription. We, have determined the X-ray crystal structure of the DNA-binding domain of, HAP1-PC7 bound to its DNA target, UAS(CYC7), and compared it to the, previously solved HAP1-wt and HAP1-18 complexes to UAS(CYC7)., Additionally, we have quantitatively compared the DNA-binding affinity and, specificity of the HAP1-PC7, HAP1-18 and HAP1-wt DNA-binding domains. We, show that, although the DNA-binding domains of these three proteins bind, UAS(CYC7) with comparable affinity and specificity, the protein-DNA, interactions are dramatically different between the three complexes., Conserved protein-DNA interactions are largely restricted to an internal, DNA sequence that excludes one of the two conserved DNA half-sites of, UAS(CYC7) suggesting a mode of recognition distinct from other HAP1 family, members. Alternative protein-DNA interactions result in divergent DNA, configurations between the three complexes. These results suggest that the, differential transcriptional activities of the HAP1, HAP1-18 and HAP1-PC7, proteins are due, at least in part, to alternative protein-DNA contacts, and implies that HAP1-DNA interactions have direct allosteric effects on, transcriptional activation.
About this Structure
1QP9 is a Single protein structure of sequence from Saccharomyces cerevisiae with ZN as ligand. Full crystallographic information is available from OCA.
Reference
Structure of HAP1-PC7 bound to DNA: implications for DNA recognition and allosteric effects of DNA-binding on transcriptional activation., Lukens AK, King DA, Marmorstein R, Nucleic Acids Res. 2000 Oct 15;28(20):3853-63. PMID:11024163
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