6b6h
From Proteopedia
The cryo-EM structure of a bacterial class I transcription activation complex
Structural highlights
Function[CRP_ECO57] A global transcription regulator. Complexes with cyclic AMP (cAMP) which allosterically activates DNA binding to regulate transcription. It can act as an activator, repressor, coactivator or corepressor. Induces a severe bend in DNA. Acts as a negative regulator of its own synthesis as well as for adenylate cyclase (cyaA), which generates cAMP. Plays a major role in carbon catabolite repression (CCR) (By similarity). [RPOC_ECO57] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOA_ECO57] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOB_ECO45] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOZ_ECO45] Promotes RNA polymerase assembly. Latches the N- and C-terminal regions of the beta' subunit thereby facilitating its interaction with the beta and alpha subunits. [RPOD_ECOLI] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This is the primary sigma factor of this bacterium. Publication Abstract from PubMedIn bacteria, the activation of gene transcription at many promoters is simple and only involves a single activator. The cyclic adenosine 3',5'-monophosphate receptor protein (CAP), a classic activator, is able to activate transcription independently through two different mechanisms. Understanding the class I mechanism requires an intact transcription activation complex (TAC) structure at a high resolution. Here we report a high-resolution cryo-electron microscopy structure of an intact Escherichia coli class I TAC containing a CAP dimer, a sigma(70)-RNA polymerase (RNAP) holoenzyme, a complete class I CAP-dependent promoter DNA, and a de novo synthesized RNA oligonucleotide. The structure shows how CAP wraps the upstream DNA and how the interactions recruit RNAP. Our study provides a structural basis for understanding how activators activate transcription through the class I recruitment mechanism. Structural basis of bacterial transcription activation.,Liu B, Hong C, Huang RK, Yu Z, Steitz TA Science. 2017 Nov 17;358(6365):947-951. doi: 10.1126/science.aao1923. PMID:29146813[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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