DNA-dependent RNA polymerases: Common structures of the active sites and possible reaction mechanisms

COMP 85

Dennis R. Salahub, dennis.salahub@ucalgary.ca, 110 Administration Building, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada and Rui Zhu, rzhu@ucalgary.ca, Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, T2N 1N4, Canada.
Almost all the known DNA-dependent RNA polymerases (RNAPs) share a universal heptapeptide, called the NADFDGD motif. Based on the available crystal structures of some of these RNAPs, we can see that this motif forms in all cases a loop with an embedded triad of aspartic acid residues. This conserved loop is the key part of the active site. We explore this common active site and possible reaction mechanisms based on the crystal structures of the yeast RNAP II. To this end, two different modeling methods, the GGA DFT method (PBE) and the reactive force field (ReaxFF), are utilized. The results using the two different methods are compared.