期刊
NUCLEIC ACIDS RESEARCH
卷 51, 期 4, 页码 1960-1970出版社
OXFORD UNIV PRESS
DOI: 10.1093/nar/gkad016
关键词
-
Canonical bacterial transcription activators bind to their cognate cis elements at the upstream of transcription start site (TSS) in a form of dimer. Caulobacter crescentus GcrA, a non-canonical transcription activator, can activate transcription from promoters harboring its cis element at the upstream or downstream of TSS in a form of monomer. The cryo-EM structures of C. crescentus GcrA-bound transcription activation complexes, GcrA TAC(U) and GcrA TAC(D), reveal the interactions between GcrA, RNAP, sigma(70), and promoter DNA, as well as the disruption of sequence-specific interaction between GcrA and DNA depending on the location of GcrA cis elements relative to TSS.
Canonical bacterial transcription activators bind to their cognate cis elements at the upstream of transcription start site (TSS) in a form of dimer. Caulobacter crescentus GcrA, a non-canonical transcription activator, can activate transcription from promoters harboring its cis element at the upstream or downstream of TSS in a form of monomer. We determined two cryo-EM structures of C. crescentus GcrA-bound transcription activation complexes, GcrA TAC(U) and GcrA TAC(D), which comprise GcrA, RNAP, sigma(70) and promoter DNA with GcrA cis elements at either the upstream or downstream of TSS at 3.6 and 3.8 angstrom, respectively. In the GcrA-TAC(U) structure, GcrA makes bipartite interactions with both sigma(70) domain 2 (sigma(70)(2)) and its cis element, while in the GcrA-TAC(D) structure, GcrA retains interaction with sigma(70)(2) but loses the interaction with its cis element. Our results suggest that GcrA likely forms a functionally specialized GcrA-RNAP-sigma(A) holoenzyme, in which GcrA first locates its cis element and then facilitates RNAP to load on core promoter at its proximal region. The sequence-specific interaction of GcrA and DNA is disrupted either at the stage of RPo formation or promoter escape depending on the location of GcrA cis elements relative to TSS.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据