Structural highlights
Function
[RPOZ_THET8] 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 (By similarity). [RPOA_THET8] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOC_THET8] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [GFH1_THET8] Inhibits all catalytic activities of RNA polymerase (RNAP) by partially occluding its substrate-binding site and preventing NTP binding.[1] [2] [3] [RPOB_THET8] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.
Publication Abstract from PubMed
The multi-subunit DNA-dependent RNA polymerase (RNAP) is the principal enzyme of transcription for gene expression. Transcription is regulated by various transcription factors. Gre factor homologue 1 (Gfh1), found in the Thermus genus, is a close homologue of the well-conserved bacterial transcription factor GreA, and inhibits transcription initiation and elongation by binding directly to RNAP. The structural basis of transcription inhibition by Gfh1 has remained elusive, although the crystal structures of RNAP and Gfh1 have been determined separately. Here we report the crystal structure of Thermus thermophilus RNAP complexed with Gfh1. The amino-terminal coiled-coil domain of Gfh1 fully occludes the channel formed between the two central modules of RNAP; this channel would normally be used for nucleotide triphosphate (NTP) entry into the catalytic site. Furthermore, the tip of the coiled-coil domain occupies the NTP beta-gamma phosphate-binding site. The NTP-entry channel is expanded, because the central modules are 'ratcheted' relative to each other by approximately 7 degrees , as compared with the previously reported elongation complexes. This 'ratcheted state' is an alternative structural state, defined by a newly acquired contact between the central modules. Therefore, the shape of Gfh1 is appropriate to maintain RNAP in the ratcheted state. Simultaneously, the ratcheting expands the nucleic-acid-binding channel, and kinks the bridge helix, which connects the central modules. Taken together, the present results reveal that Gfh1 inhibits transcription by preventing NTP binding and freezing RNAP in the alternative structural state. The ratcheted state might also be associated with other aspects of transcription, such as RNAP translocation and transcription termination.
Crystal structure of bacterial RNA polymerase bound with a transcription inhibitor protein.,Tagami S, Sekine S, Kumarevel T, Hino N, Murayama Y, Kamegamori S, Yamamoto M, Sakamoto K, Yokoyama S Nature. 2010 Dec 16;468(7326):978-82. Epub 2010 Dec 1. PMID:21124318[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hogan BP, Hartsch T, Erie DA. Transcript cleavage by Thermus thermophilus RNA polymerase. Effects of GreA and anti-GreA factors. J Biol Chem. 2002 Jan 11;277(2):967-75. Epub 2001 Oct 17. PMID:11606592 doi:http://dx.doi.org/10.1074/jbc.M108737200
- ↑ Laptenko O, Borukhov S. Biochemical assays of Gre factors of Thermus thermophilus. Methods Enzymol. 2003;371:219-32. PMID:14712703 doi:http://dx.doi.org/10.1016/S0076-6879(03)71016-7
- ↑ Symersky J, Perederina A, Vassylyeva MN, Svetlov V, Artsimovitch I, Vassylyev DG. Regulation through the RNA polymerase secondary channel. Structural and functional variability of the coiled-coil transcription factors. J Biol Chem. 2006 Jan 20;281(3):1309-12. Epub 2005 Nov 18. PMID:16298991 doi:10.1074/jbc.C500405200
- ↑ Tagami S, Sekine S, Kumarevel T, Hino N, Murayama Y, Kamegamori S, Yamamoto M, Sakamoto K, Yokoyama S. Crystal structure of bacterial RNA polymerase bound with a transcription inhibitor protein. Nature. 2010 Dec 16;468(7326):978-82. Epub 2010 Dec 1. PMID:21124318 doi:10.1038/nature09573
