转录因子IIB、TATA结合蛋白与DNA之间的相互依存相互作用。
Interdependent interactions between TFIIB, TATA binding protein, and DNA.
作者信息
Buratowski Robin M, Downs Jessica, Buratowski Stephen
机构信息
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
出版信息
Mol Cell Biol. 2002 Dec;22(24):8735-43. doi: 10.1128/MCB.22.24.8735-8743.2002.
Temperature-sensitive mutants of TFIIB that are defective for essential interactions were isolated. One mutation (G204D) results in disruption of a protein-protein contact between TFIIB and TATA binding protein (TBP), while the other (K272I) disrupts an interaction between TFIIB and DNA. The TBP gene was mutagenized, and alleles that suppress the slow-growth phenotypes of the TFIIB mutants were isolated. TFIIB with the G204D mutation [TFIIB(G204D)] was suppressed by hydrophobic substitutions at lysine 239 of TBP. These changes led to increased affinity between TBP and TFIIB. TFIIB(K272I) was weakly suppressed by TBP mutants in which K239 was changed to hydrophobic residues. However, this mutant TFIIB was strongly suppressed by conservative substitutions in the DNA binding surface of TBP. Biochemical characterization showed that these TBP mutants had increased affinity for a TATA element. The TBPs with increased affinity could not suppress TFIIB(G204D), leading us to propose a two-step model for the interaction between TFIIB and the TBP-DNA complex.
分离出了在关键相互作用方面存在缺陷的TFIIB温度敏感突变体。一种突变（G204D）导致TFIIB与TATA结合蛋白（TBP）之间的蛋白质-蛋白质接触被破坏，而另一种突变（K272I）则破坏了TFIIB与DNA之间的相互作用。对TBP基因进行诱变，并分离出抑制TFIIB突变体慢生长表型的等位基因。具有G204D突变的TFIIB [TFIIB(G204D)] 被TBP赖氨酸239处的疏水取代所抑制。这些变化导致TBP与TFIIB之间的亲和力增加。TFIIB(K272I) 被K239变为疏水残基的TBP突变体微弱抑制。然而，这种突变的TFIIB被TBP DNA结合表面的保守取代强烈抑制。生化特性表明，这些TBP突变体对TATA元件的亲和力增加。亲和力增加的TBP不能抑制TFIIB(G204D)，这使我们提出了TFIIB与TBP-DNA复合物之间相互作用的两步模型。
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