Burley S K
Laboratories of Molecular Biophysics, Rockefeller University, New York 10021, USA.
Philos Trans R Soc Lond B Biol Sci. 1996 Apr 29;351(1339):483-9. doi: 10.1098/rstb.1996.0046.
TATA box-binding protein (TBP) is required by all three eukaryotic RNA polymerases for correct initiation of transcription of ribosomal, messenger, small nuclear and transfer RNAs. Since the first gene encoding a TBP was cloned, it has been the object of considerable biochemical and genetic study. Substantial progress has also been made on structural and mechanistic studies, including our three-dimensional crystal structures of TBP, TBP bound to a consensus TATA elements, and the ternary complex of transcription factor IIB (TFIIB) recognizing TBP bound to a TATA element. The structure of apo TBP was determined at 2.1 A resolution. This highly symmetric alpha/beta structure represents a new DNA-binding fold, which resembles a molecular "saddle' that sits astride the DNA. The DNA-binding surface is a novel curved, antiparallel beta-sheet. The structure of TBP complexed with the TATA element of the Adenovirus major late promoter was determined at 1.9 A resolution. Binding of the protein induces a dramatic conformational change in the DNA, by tracking the minor groove and inducing two sharp kinks at either end of the sequence TATAAAAG. Between the kinks, the right-handed double helix is smoothly curved and partly unwound, presenting a widened minor groove to TBP's concave, antiparallel beta-sheet. Side chain-base interactions are completely restricted to the minor groove, and include hydrogen bonds, van der Waals contacts and phenylalanine-base stacking interactions. The structure of a TFIIB/TBP/TATA element ternary complex was determined at 2.7 A resolution. Core TFIIB resembles cyclinA, and recognizes the preformed TBP-DNA complex via protein-protein and protein-DNA interactions. The N-terminal domain of core TFIIB forms the downstream surface of the ternary complex, where it could fix the transcription start site. The remaining surfaces of TBP and the TFIIB can interact with TBP-associated factors, other class II initiation factors, and transcriptional activators and coactivators.
所有三种真核生物RNA聚合酶在核糖体RNA、信使RNA、小核RNA和转运RNA转录的正确起始过程中都需要TATA框结合蛋白（TBP）。自从第一个编码TBP的基因被克隆以来，它一直是大量生化和遗传学研究的对象。在结构和机制研究方面也取得了重大进展，包括我们解析的TBP、与共有TATA元件结合的TBP以及识别与TATA元件结合的TBP的转录因子IIB（TFIIB）三元复合物的三维晶体结构。无配体TBP的结构在2.1埃分辨率下得以确定。这种高度对称的α/β结构代表了一种新的DNA结合折叠，类似于横跨DNA的分子“鞍座”。DNA结合表面是一个新颖的弯曲反平行β折叠片。与腺病毒主要晚期启动子的TATA元件复合的TBP结构在1.9埃分辨率下得以确定。该蛋白的结合通过追踪小沟并在序列TATAAAAG的两端诱导两个急剧的扭结，从而在DNA中引发显著的构象变化。在扭结之间，右手双螺旋平滑弯曲并部分解旋，向TBP的凹形反平行β折叠片呈现出变宽的小沟。侧链与碱基的相互作用完全局限于小沟，包括氢键、范德华接触和苯丙氨酸与碱基的堆积相互作用。TFIIB/TBP/TATA元件三元复合物的结构在2.7埃分辨率下得以确定。核心TFIIB类似于细胞周期蛋白A，并通过蛋白质-蛋白质和蛋白质-DNA相互作用识别预先形成的TBP-DNA复合物。核心TFIIB的N端结构域形成三元复合物的下游表面，在那里它可以确定转录起始位点。TBP和TFIIB的其余表面可以与TBP相关因子、其他II类起始因子以及转录激活剂和共激活剂相互作用。
