7aoe
From Proteopedia
Schizosaccharomyces pombe RNA polymerase I (elongation complex)
Structural highlights
FunctionRPA1_SCHPO DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Largest and catalytic core component of RNA polymerase I which synthesizes ribosomal RNA precursors. Forms the polymerase active center together with the second largest subunit. A single stranded DNA template strand of the promoter is positioned within the central active site cleft of Pol I. A bridging helix emanates from RPA1 and crosses the cleft near the catalytic site and is thought to promote translocation of Pol I by acting as a ratchet that moves the RNA-DNA hybrid through the active site by switching from straight to bent conformations at each step of nucleotide addition (By similarity).[UniProtKB:P10964] Publication Abstract from PubMedRNA polymerase (Pol) I transcribes the ribosomal RNA precursor in all eukaryotes. The mechanisms 'activation by cleft contraction' and 'hibernation by dimerization' are unique to the regulation of this enzyme, but structure-function analysis is limited to baker's yeast. To understand whether regulation by such strategies is specific to this model organism or conserved among species, we solve three cryo-EM structures of Pol I from Schizosaccharomyces pombe in different functional states. Comparative analysis of structural models derived from high-resolution reconstructions shows that activation is accomplished by a conserved contraction of the active center cleft. In contrast to current beliefs, we find that dimerization of the S. pombe polymerase is also possible. This dimerization is achieved independent of the 'connector' domain but relies on two previously undescribed interfaces. Our analyses highlight the divergent nature of Pol I transcription systems from their counterparts and suggest conservation of regulatory mechanisms among organisms. Conserved strategies of RNA polymerase I hibernation and activation.,Heiss FB, Daiss JL, Becker P, Engel C Nat Commun. 2021 Feb 3;12(1):758. doi: 10.1038/s41467-021-21031-8. PMID:33536435[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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