2c35: Difference between revisions

[[Image:2c35.gif|left|200px]]<br /><applet load="2c35" size="350" color="white" frame="true" align="right" spinBox="true"  

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.

2C35 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/DNA-directed_RNA_polymerase DNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.6 2.7.7.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2C35 OCA].  

[[Category: Cordell, S C.]]

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