BACTERIAL RNA POLYMERASE ? FACTOR INTERACTIONS WITH THE PROMOTER -10 ELEMENT

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 在细菌中，450 kDa RNA聚合酶（RNAP）全酶，包括进化上保守的催化核心（亚基组成<$2 <$“）与启动特异性<$因子结合，指导转录起始。当与RNAP复合时，仅结合启动子DNA的主要因子将RNAP招募到含有保守的启动子上， 10（TATAAT共识为<$70）和 35（TTGACA）启动子元件。一旦与封闭复合物中的启动子结合（其是瞬时的且相对不稳定的），全酶自发地异构化为有转录能力的开放复合物，其中来自DNA的双链DNA被转录。 转录起始位点下游的转录元件被熔化以形成转录泡。该因子在开放复合物形成中起关键作用，部分是通过与转录泡内-10元件的单链非模板链的序列特异性结合。我们的目标是确定高分辨率的晶体结构之间的复合物和-10元素DNA可视化这种相互作用的启动子熔化的关键。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In bacteria, the 450 kDa RNA polymerase (RNAP) holoenzyme, comprising the evolutionarily conserved catalytic core (subunit composition ¿2¿¿'¿) combined with the initiation-specific ¿ factor, directs transcription initiation. The primary ¿ factor, which only binds promoter DNA when complexed with RNAP, recruits RNAP to promoters containing conserved 10 (TATAAT consensus for ¿70) and 35 (TTGACA) promoter elements. Once bound to the promoter in a closed complex (which is transient and relatively unstable), the holoenzyme spontaneously isomerizes to the transcription-competent open complex, in which the double-stranded DNA from the 10 element downstream to the transcription start site is melted to form the transcription bubble. The ¿ factor plays a key role in open complex formation, in part by sequence-specific binding to the single-stranded, nontemplate strand of the -10 element within the transcription bubble. Our goal is to determine high-resolution crystal structures of complexes between ¿ and -10 element DNA to visualize this interaction critical for promoter melting.