1pcz
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STRUCTURE OF TATA-BINDING PROTEIN
OverviewOverview
This study analyzes the three-dimensional structure of the TATA-box, binding protein (TBP) from the hyperthermophilic archaea Pyrococcus, woesei. The crystal structure of P. woesei TBP (PwTBP) was solved at 2.2 A, by X-ray diffraction and as expected from sequence homology (36% to 41%, identical to eukaryotic TBPs) its overall structure is very similar to, eukaryotic TBPs. The thermal unfolding transition temperature of this, protein was measured by differential scanning calorimetry to be 101, degrees C, which is more than 40 degrees C higher than that of yeast TBP., Preliminary titration calorimetry data show that the affinity of PwTBP for, its DNA target, unlike its eukaryotic counterparts, is enhanced by, increasing the temperature and salt concentration. The structure reveals, possible explanations for this thermostability and these unusual DNA, binding properties. The crystal structure of this hyperthermostable, protein was compared to its mesophilic homologs and analyzed for, differences in the native structure that may contribute to, thermostability. Differences found were: (1) a disulfide bond not found in, mesophilic counterparts; (2) an increased number of surface electrostatic, interactions; (3) more compact protein packing. The presumed DNA binding, surface of PwTBP, like its eukaryotic counterparts, is hydrophobic but the, electrostatic profile surrounding the protein is relatively neutral, compared to the asymmetric positive potential that surrounds eukaryotic, TBPs. The total reliance on a hydrophobic interface with DNA may explain, the enhanced affinity of PwTBP for its DNA promoter at higher temperatures, and increased salt concentration.
About this StructureAbout this Structure
1PCZ is a Single protein structure of sequence from Pyrococcus woesei. Full crystallographic information is available from OCA.
ReferenceReference
The crystal structure of a hyperthermophilic archaeal TATA-box binding protein., DeDecker BS, O'Brien R, Fleming PJ, Geiger JH, Jackson SP, Sigler PB, J Mol Biol. 1996 Dec 20;264(5):1072-84. PMID:9000631
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