2c35
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SUBUNITS RPB4 AND RPB7 OF HUMAN RNA POLYMERASE II
OverviewOverview
The Rpb4 and Rpb7 subunits of eukaryotic RNA polymerase II (RNAP(II)) form a heterodimer that protrudes from the 10-subunit core of the enzyme. We have obtained crystals of the human Rpb4/Rpb7 heterodimer and determined the structure to 2.7 A resolution. The presence of putative RNA-binding domains on the Rpb7 subunit and the position of the heterodimer close to the RNA exit groove in the 12 subunit yeast polymerase complex strongly suggests a role for the heterodimer in binding and stabilizing the nascent RNA transcript. We have complemented the structural analysis with biochemical studies directed at dissecting the RNA-binding properties of the human Rpb4/Rpb7 complex and that of the homologous E/F complex from Methanocaldococcus jannaschii. A number of conserved, solvent-exposed residues in both the human Rpb7 subunit and the archaeal E subunit have been modified by site-directed mutagenesis and the mutants tested for RNA binding by performing electrophoretic mobility shift assays. These studies have identified an elongated surface region on the corresponding face of both subunit E and Rpb7 that is involved in RNA binding. The area spans the nucleic acid binding face of the OB fold, including the B4-B5 loop, but also extends towards the N-terminal domain.
About this StructureAbout this Structure
2C35 is a Protein complex structure of sequences from Homo sapiens. Active as DNA-directed RNA polymerase, with EC number 2.7.7.6 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure and RNA binding of the Rpb4/Rpb7 subunits of human RNA polymerase II., Meka H, Werner F, Cordell SC, Onesti S, Brick P, Nucleic Acids Res. 2005 Nov 10;33(19):6435-44. Print 2005. PMID:16282592
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