Summary: Bacterial RNA polymerase, alpha chain C terminal domain
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Bacterial RNA polymerase, alpha chain C terminal domain Provide feedback
The alpha subunit of RNA polymerase consists of two independently folded domains, referred to as amino-terminal and carboxyl terminal domains. The amino terminal domain is involved in the interaction with the other subunits of the RNA polymerase. The carboxyl-terminal domain interacts with the DNA and activators. The amino acid sequence of the alpha subunit is conserved in prokaryotic and chloroplast RNA polymerases. There are three regions of particularly strong conservation, two in the amino-terminal and one in the carboxyl- terminal .
Jeon YH, Negishi T, Shirakawa M, Yamazaki T, Fujita N, Ishihama A, Kyogoku Y; , Science 1995;270:1495-1497.: Solution structure of the activator contact domain of the RNA polymerase alpha subunit. PUBMED:7491496 EPMC:7491496
Murakami K, Kimura M, Owens JT, Meares CF, Ishihama A; , Proc Natl Acad Sci USA 1997;94:1709-1714.: The two alpha subunits of Escherichia coli RNA polymerase are asymmetrically arranged and contact different halves of the DNA upstream element. PUBMED:9050843 EPMC:9050843
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR011260
The core of the bacterial RNA polymerase (RNAP) consists of four subunits, two alpha, a beta and a beta', which are conserved from bacteria to mammals. The alpha subunit (RpoA) initiates RNAP assembly by dimerising to form a platform on which the beta subunits can interact. The alpha subunit consists of a N-terminal domain (NTD) and a C-terminal domain (CTD), connected by a short linker. The NTD is essential for RNAP assembly, while the CTD is necessary for transcription regulation, interacting with transcription factors and promoter upstream elements. In Escherichia coli, the catabolite activator protein (CAP or CRP) was shown to exert its effect through its interactions with the CTD, where CAP binding to CTD promotes RNAP binding to promoter DNA, thereby stimulating transcription initiation at class I CAP-dependent promoters. At class II CAP-dependent promoters, the interaction of CAP with CTD is one of multiple interactions involved in activation [PUBMED:12202833].
The CTD has a compact structure of four helices and two long arms enclosing its hydrophobic core, making its folding topology distinct from most other binding proteins. The upstream promoter element-binding site is formed from helices 1 and 4 [PUBMED:7491496].
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|Molecular function||DNA-directed RNA polymerase activity (GO:0003899)|
|DNA binding (GO:0003677)|
|Biological process||transcription, DNA-dependent (GO:0006351)|
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This superfamily includes Helix-hairpin-helix DNA-binding domains.
The clan contains the following 20 members:Cdd1 DNA_pol_lambd_f DUF3173 DUF4332 DUF655 HHH HhH-GPD HHH_2 HHH_3 HHH_4 HHH_5 HHH_6 HHH_7 HHH_8 IMS_HHH PsbU RNA_pol_A_CTD T2SK TfoX_C Transposase_20
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Curation and family details
|Seed source:||Pfam-B_172 (release 3.0)|
|Author:||Finn RD, Bateman A|
|Number in seed:||121|
|Number in full:||5961|
|Average length of the domain:||65.70 aa|
|Average identity of full alignment:||44 %|
|Average coverage of the sequence by the domain:||20.39 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||10|
|Download:||download the raw HMM for this family|
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There is 1 interaction for this family. More...
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the RNA_pol_A_CTD domain has been found. There are 22 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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