Crystal structure of a transcription factor IIIB core interface ternary complex
Crystal structure of a transcription factor IIIB core interface ternary complex
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DOI：
10.1038/nature01534
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发表时间：
2003-04-03
期刊：
影响因子：
64.8
通讯作者：
Sigler, PB
中科院分区：
文献类型：
--
作者：
Juo, ZS;Kassavetis, GA;Sigler, PB
转录因子IIIB（TFIIIB）由TATA结合蛋白（TBP）、TFIIIB相关因子（Brf 1）和Bdp 1组成，是RNA聚合酶III 1 -4的基础和调节转录的核心组分。TFIIIB将其聚合酶募集到启动子，随后在开放起始复合物的形成中起重要作用。Brf 1的氨基末端一半与聚合酶II通用转录因子TFIIB具有高度的序列相似性，但Brf 1的羧基末端一半贡献了其与TBP 5 -8的大部分结合亲和力。主要锚定区位于酵母Brf 1的残基435和545之间，包含其同源结构域II。同一区域还提供了将Bdp 1组装成TFIIIB复合物的主要界面（9）。我们在这里报告了一个2.95埃分辨率的晶体结构的三元复合物含有Brf 1同源结构域II，TBP的保守区和19个碱基对的U6启动子DNA。该结构揭示了TFIIIB组装的核心界面，并展示了松散包装的Brf 1结构域如何与TBP的凸面和侧面实现显着的结合特异性。
Transcription factor IIIB ( TFIIIB), consisting of the TATA-binding protein (TBP), TFIIB-related factor (Brf1) and Bdp1, is a central component in basal and regulated transcription by RNA polymerase III1-4. TFIIIB recruits its polymerase to the promoter and subsequently has an essential role in the formation of the open initiation complex. The amino-terminal half of Brf1 shares a high degree of sequence similarity with the polymerase II general transcription factor TFIIB, but it is the carboxy-terminal half of Brf1 that contributes most of its binding affinity with TBP5-8. The principal anchoring region is located between residues 435 and 545 of yeast Brf1, comprising its homology domain II. The same region also provides the primary interface for assembling Bdp1 into the TFIIIB complex(9). We report here a 2.95 Angstrom resolution crystal structure of the ternary complex containing Brf1 homology domain II, the conserved region of TBP and 19 base pairs of U6 promoter DNA. The structure reveals the core interface for assembly of TFIIIB and demonstrates how the loosely packed Brf1 domain achieves remarkable binding specificity with the convex and lateral surfaces of TBP.