| Structural highlights
4xlr is a 20 chain structure with sequence from Atcc 25104, Thermus aquaticus and Thermus thermophilus jl-18. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , |
| Related: | 4xln, 4xlp, 4xlq, 4xls, 4xax |
| Gene: | sigA (ATCC 25104), TtJL18_0238 (Thermus thermophilus JL-18) |
| Activity: | DNA-directed RNA polymerase, with EC number 2.7.7.6 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[RPOZ_THEAQ] 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.[1] [SIGA_THEAQ] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This sigma factor is the primary sigma factor during exponential growth.[HAMAP-Rule:MF_00963][2] [3]
Publication Abstract from PubMed
A key point to regulate gene expression is at transcription initiation, and activators play a major role. CarD, an essential activator in Mycobacterium tuberculosis, is found in many bacteria, including Thermus species, but absent in Escherichia coli. To delineate the molecular mechanism of CarD, we determined crystal structures of Thermus transcription initiation complexes containing CarD. The structures show CarD interacts with the unique DNA topology presented by the upstream double-stranded/single-stranded DNA junction of the transcription bubble. We confirm that our structures correspond to functional activation complexes, and extend our understanding of the role of a conserved CarD Trp residue that serves as a minor groove wedge, preventing collapse of the transcription bubble to stabilize the transcription initiation complex. Unlike E. coli RNAP, many bacterial RNAPs form unstable promoter complexes, explaining the need for CarD.
CarD uses a minor groove wedge mechanism to stabilize the RNA polymerase open promoter complex.,Bae B, Chen J, Davis E, Leon K, Darst SA, Campbell EA Elife. 2015 Sep 8;4. doi: 10.7554/eLife.08505. PMID:26349034[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Minakhin L, Bhagat S, Brunning A, Campbell EA, Darst SA, Ebright RH, Severinov K. Bacterial RNA polymerase subunit omega and eukaryotic RNA polymerase subunit RPB6 are sequence, structural, and functional homologs and promote RNA polymerase assembly. Proc Natl Acad Sci U S A. 2001 Jan 30;98(3):892-7. PMID:11158566 doi:http://dx.doi.org/10.1073/pnas.98.3.892
- ↑ Minakhin L, Nechaev S, Campbell EA, Severinov K. Recombinant Thermus aquaticus RNA polymerase, a new tool for structure-based analysis of transcription. J Bacteriol. 2001 Jan;183(1):71-6. PMID:11114902 doi:http://dx.doi.org/10.1128/JB.183.1.71-76.2001
- ↑ Campbell EA, Muzzin O, Chlenov M, Sun JL, Olson CA, Weinman O, Trester-Zedlitz ML, Darst SA. Structure of the bacterial RNA polymerase promoter specificity sigma subunit. Mol Cell. 2002 Mar;9(3):527-39. PMID:11931761
- ↑ Bae B, Chen J, Davis E, Leon K, Darst SA, Campbell EA. CarD uses a minor groove wedge mechanism to stabilize the RNA polymerase open promoter complex. Elife. 2015 Sep 8;4. doi: 10.7554/eLife.08505. PMID:26349034 doi:http://dx.doi.org/10.7554/eLife.08505
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