Abstract
RPB5 is an essential subunit of eukaryotic RNA polymerase II. It has been proposed to interact with DNA and several key transcription factors during transcription. These interactions are crucial for transcription and its regulation. Here, prior to obtaining complex structures of human RPB5 and its binding partners, recombinant human RPB5 was crystallized alone by vapour diffusion in hanging drops. A complete data set was collected from a single frozen crystal employing an in-house X-ray source. The crystal diffracted to 2.8 Å resolution and belonged to space group P4(3)2(1)2. The likely Matthews coefficient and solvent content of 2.67 Å(3) Da(-1) and 53.92%, respectively, suggested the presence of two protein subunits in the asymmetric unit. The structure was solved using molecular replacement.