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

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在细菌中，450 kDa RNA聚合酶(RNAP)全酶由进化上保守的催化核心(亚基组成)和启动特异性因子组成，指导转录启动。初级因子与RNAP结合时只与启动子DNA结合，将RNAP招募到含有保守的10(TATAAT共识为70)和35(TTGACA)启动子元件的启动子上。一旦与闭合复合体中的启动子结合(这是暂时的且相对不稳定的)，全酶自发异构化为具有转录能力的开放复合体，在开放复合体中，从10元件下游到转录起始点的双链DNA被熔化，形成转录泡。该因子在开放复合体的形成中起关键作用，部分是通过序列特异性地与转录泡内-10元件的单链、非模板链结合。我们的目标是确定与-10元素DNA之间的络合物的高分辨率晶体结构，以可视化这种相互作用对启动子熔化至关重要。

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.