Evidence for a tyrosine-adenine stacking interaction and for a short-lived open intermediate subsequent to initial binding of Escherichia coli RNA polymerase to promoter DNA.
Evidence for a tyrosine-adenine stacking interaction and for a short-lived open intermediate subsequent to initial binding of Escherichia coli RNA polymerase to promoter DNA.
复制标题
DOI：
10.1016/j.jmb.2008.10.023
复制
发表时间：
2009-01-16
影响因子：
5.6
通讯作者：
deHaseth, Pieter L.
中科院分区：
文献类型：
--
作者：
Schroeder, Lisa A.;Gries, Theodore J.;Saecker, Ruth M.;Record, M. Thomas, Jr.;Harris, Michael E.;deHaseth, Pieter L.
细菌RNA聚合酶和“sigma”转录因子通过破坏约14个碱基对在启动子处形成有起始能力的“开放”复合物。链分离可能在高度保守的-11 A-T碱基对处开始。主要E.大肠杆菌σ因子σ70参与了这一过程，但它们的作用尚不清楚。为了监测加入RNA聚合酶后特定碱基的命运，检测了在启动子DNA的-11和另外两个位置上带有荧光A-类似物2-AP单取代的启动子。获得的证据表明，在开放复合物形成的途径上存在开放中间体，其中这些2-AP不再堆叠在其相邻的碱基上。在σ70的2.3区的430位残基上的酪氨酸被证明参与淬灭在−11位取代的2-AP的荧光，推测是通过堆积相互作用。这些数据完善了开放复合物形成的结构模型，并揭示了一种新的相互作用，参与DNA熔化的RNA聚合酶。
Bacterial RNA polymerase and a “sigma” transcription factor form an initiation-competent “open” complex at a promoter by disruption of about 14 base pairs. Strand separation is likely initiated at the highly conserved -11 A-T base pair. Amino acids in conserved region 2.3 of the main E. coli sigma factor, σ70, are involved in this process, but their roles are unclear. To monitor the fates of particular bases upon addition of RNA polymerase, promoters bearing single substitutions of the fluorescent A-analog 2-AP at −11 and two other positions in promoter DNA were examined. Evidence was obtained for an open intermediate on the pathway to open complex formation, in which these 2-AP are no longer stacked onto their neighboring bases. The tyrosine at residue 430 in region 2.3 of σ70 was shown to be involved in quenching the fluorescence of a 2-AP substituted at −11, presumably through a stacking interaction. These data refine the structural model for open complex formation and reveal a novel interaction involved in DNA melting by RNA polymerase.
登录
查看更多内容
影响因子：
3.2
作者：
Barinova, N.;Zhilina, E.;Kulbachinskiy, A.
通讯作者：
Kulbachinskiy, A.
影响因子：
5.6
作者：
Liebert, K;Hermann, A;Jeltsch, A
通讯作者：
Jeltsch, A
影响因子：
5.6
作者：
Reddy, YVR;Rao, DN
通讯作者：
Rao, DN
影响因子：
64.8
作者：
BURGESS, RR;TRAVERS, AA;BAUTZ, EKF
通讯作者：
BAUTZ, EKF
影响因子：
5.6
作者：
Craig, ML;Tsodikov, OV;Record, MT
通讯作者：
Record, MT