Interdependent interactions between TFIIB, TATA binding protein, and DNA
Interdependent interactions between TFIIB, TATA binding protein, and DNA
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DOI：
10.1128/mcb.22.24.8735-8743.2002
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发表时间：
2002-12-01
影响因子：
5.3
通讯作者：
Buratowski, S
中科院分区：
文献类型：
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作者：
Buratowski, RM;Downs, J;Buratowski, S
分离了TFIIB的温度敏感突变体，这些突变体在基本相互作用方面存在缺陷。一种突变（G204D）导致TFIIB和TATA结合蛋白（TBP）之间的蛋白蛋白接触中断，而另一种突变（K272I）破坏TFIIB和DNA之间的相互作用。对TBP基因进行诱变，分离出抑制TFIIB突变体缓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的疏水取代所抑制。这些变化导致TBP和TFIIB之间的亲和力增加。TBP突变体将K239转变为疏水残基，TFIIB（K2721）被弱抑制。然而，该突变体TFIIB被TBP DNA结合表面的保守取代强烈抑制。生化表征表明，这些TBP突变体对TATA元素的亲和力增加。亲和性增加的TBPs不能抑制TFIIB(G204D)，因此我们提出了TFIIB与TBP-DNA复合物相互作用的两步模型。
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(K2721) 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.