FAST FOLDING MUTANTS OF TETRAHYMENA RIBOZYME

TBP的三维结构由两个几乎相同的结构组成， 采用鞍形的相同域。 凹下表面 这种鞍形蛋白质的C末端结构域由以下组成 高度弯曲的反平行线包含所有氨基的片层 与DNA结合有关的酸。 所述表面的凸形上表面 鞍状体含有对与其它生物相互作用重要的残基， 转录因子 DNA结合位点由两对 在凹鞍的两侧有苯丙氨酸残基。 这些 预计残基在未结合的 单体蛋白 然而，是否非保守的N-末端 结构域与这些残基的相互作用是未知的。 同样， 蛋白质的DNA结合位点的溶剂可及性 低聚TBP也是未知的。 这些问题的答案是 理解约束机制的根本重要性， 该蛋白质的功能。 本研究的主要目的是比较 这些未结合苯丙氨酸残基的溶剂可及性 单体TBP、寡聚TBP和TBP-DNA复合物。 初步质量 Hspectrometric研究表明，含有苯丙氨酸的 在暴露于以下条件时，Hpeptide在4 msec的时间尺度内发生修饰： Hbeamline X9A。

The three dimensional structure of TBP consists of two nearly identical domains that adopt a saddle shape. The concave undersurface of the C-terminal domain of this saddle-shaped protein consists of highly curved antiparallel ?-sheets which contain all of the amino acids implicated in DNA binding. The convex upper surface of the saddle contains residues important for interactions with other transcription factors. The DNA binding sites consist of two pairs of phenylalanine residues on both sides of the concave saddle. These residues are predicted to be solvent accessible in the unbound monomeric protein. However, whether the non-conserved N-terminal domain interacts with these residues is not known. Similarly, the solvent accessibility of the DNA-binding site of the protein in oligomeric TBP is also not known. Answers to these questions are of fundamental importance to understanding the mechanism of binding and function of this protein. The initial aim of this study is to compare the solvent accessibility of these phenylalanine residues in unbound monomeric TBP, oligomeric TBP and TBP-DNA complexes. Preliminary mass Hspectrometric studies have revealed that the phenylalanine containing Hpeptides are modified in a time scale of 4 msec upon exposure at Hbeamline X9A.