7z1m

From Proteopedia

Structure of yeast RNA Polymerase III Elongation Complex (EC)

Structural highlights

7z1m is a 10 chain structure with sequence from Saccharomyces cerevisiae W303 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 3.4Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RPAB2_YEAST DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and small RNAs, such as 5S rRNA and tRNAs, respectively. Pol II is the central component of the basal RNA polymerase II transcription machinery. Pols are composed of mobile elements that move relative to each other. In Pol II, RPB6 is part of the clamp element and togther with parts of RPB1 and RPB2 forms a pocket to which the RPB4-RPB7 subcomplex binds (By similarity).

Publication Abstract from PubMed

RNA polymerase (Pol) III is specialized to transcribe short, abundant RNAs, for which it terminates transcription on polythymine (dT) stretches on the non-template (NT) strand. When Pol III reaches the termination signal, it pauses and forms the pre-termination complex (PTC). Here, we report cryoelectron microscopy (cryo-EM) structures of the yeast Pol III PTC and complementary functional states at resolutions of 2.7-3.9 A. Pol III recognizes the poly(dT) termination signal with subunit C128 that forms a hydrogen-bond network with the NT strand and, thereby, induces pausing. Mutating key interacting residues interferes with transcription termination in vitro, impairs yeast growth, and causes global termination defects in vivo, confirming our structural results. Additional cryo-EM analysis reveals that C53-C37, a Pol III subcomplex and key termination factor, participates indirectly in Pol III termination. We propose a mechanistic model of Pol III transcription termination and rationalize why Pol III, unlike Pol I and Pol II, terminates on poly(dT) signals.

Architecture of the yeast Pol III pre-termination complex and pausing mechanism on poly(dT) termination signals.,Girbig M, Xie J, Grotsch H, Libri D, Porrua O, Muller CW Cell Rep. 2022 Sep 6;40(10):111316. doi: 10.1016/j.celrep.2022.111316. PMID:36070694^[1]

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

References

↑ Girbig M, Xie J, Grötsch H, Libri D, Porrua O, Müller CW. Architecture of the yeast Pol III pre-termination complex and pausing mechanism on poly(dT) termination signals. Cell Rep. 2022 Sep 6;40(10):111316. PMID:36070694 doi:10.1016/j.celrep.2022.111316