3nfi
From Proteopedia
Crystal structure of tandem winged helix domain of RNA polymerase I subunit A49
Structural highlights
FunctionRPA49_YEAST DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase I which synthesizes ribosomal RNA precursors. A49 is easily dissociated from the rest of pol A (pol I), producing the form A*, which shows impaired transcriptional activity and increased sensitivity to alpha-amanitin. The function of A49 might be linked to the RNase H activity that was found associated with this subunit. 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 PubMedThe eukaryotic RNA polymerases Pol I, II, and III use different promoters to transcribe different classes of genes. Promoter usage relies on initiation factors, including TFIIF and TFIIE, in the case of Pol II. Here, we show that the Pol I-specific subunits A49 and A34.5 form a subcomplex that binds DNA and is related to TFIIF and TFIIE. The N-terminal regions of A49 and A34.5 form a dimerization module that stimulates polymerase-intrinsic RNA cleavage and has a fold that resembles the TFIIF core. The C-terminal region of A49 forms a "tandem winged helix" (tWH) domain that binds DNA with a preference for the upstream promoter nontemplate strand and is predicted in TFIIE. Similar domains are predicted in Pol III-specific subunits. Thus, Pol I/III subunits that have no counterparts in Pol II are evolutionarily related to Pol II initiation factors and may have evolved to mediate promoter specificity and transcription processivity. RNA polymerase I contains a TFIIF-related DNA-binding subcomplex.,Geiger SR, Lorenzen K, Schreieck A, Hanecker P, Kostrewa D, Heck AJ, Cramer P Mol Cell. 2010 Aug 27;39(4):583-94. PMID:20797630[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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