2o5j

From Proteopedia

Crystal structure of the T. thermophilus RNAP polymerase elongation complex with the NTP substrate analog

Structural highlights

2o5j is a 16 chain structure with sequence from Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

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).

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The mechanism of substrate loading in multisubunit RNA polymerase is crucial for understanding the general principles of transcription yet remains hotly debated. Here we report the 3.0-A resolution structures of the Thermus thermophilus elongation complex (EC) with a non-hydrolysable substrate analogue, adenosine-5'-[(alpha,beta)-methyleno]-triphosphate (AMPcPP), and with AMPcPP plus the inhibitor streptolydigin. In the EC/AMPcPP structure, the substrate binds to the active ('insertion') site closed through refolding of the trigger loop (TL) into two alpha-helices. In contrast, the EC/AMPcPP/streptolydigin structure reveals an inactive ('preinsertion') substrate configuration stabilized by streptolydigin-induced displacement of the TL. Our structural and biochemical data suggest that refolding of the TL is vital for catalysis and have three main implications. First, despite differences in the details, the two-step preinsertion/insertion mechanism of substrate loading may be universal for all RNA polymerases. Second, freezing of the preinsertion state is an attractive target for the design of novel antibiotics. Last, the TL emerges as a prominent target whose refolding can be modulated by regulatory factors.

Structural basis for substrate loading in bacterial RNA polymerase.,Vassylyev DG, Vassylyeva MN, Zhang J, Palangat M, Artsimovitch I, Landick R Nature. 2007 Jul 12;448(7150):163-8. Epub 2007 Jun 20. PMID:17581591^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Vassylyev DG, Vassylyeva MN, Zhang J, Palangat M, Artsimovitch I, Landick R. Structural basis for substrate loading in bacterial RNA polymerase. Nature. 2007 Jul 12;448(7150):163-8. Epub 2007 Jun 20. PMID:17581591 doi:10.1038/nature05931