Characterization and Crystallization of the Mycobacterium Tuberculosis trmD

Abstract

CHARACTERIZATION OF THE MYCOBACTERIUM TUBERCULOSIS TRMD By Zohal Hamidi Bachelor of Science, Virginia Polytechnic Institute & State University, 2006 A thesis submitted in partial fulfillment of the requirements for the degree of Master’s of Science at Virginia Commonwealth University. Virginia Commonwealth University, 2010 Major Director: Dr. Walter M. Holmes Biochemistry Professor in Department of Microbiology & Immunology One third of the world’s population is affected by Tuberculosis (TB), a disease caused by infection with Mycobacterium tuberculosis. The emergence of multidrugresistant MtB makes this disease a major public health concern. New agents are needed to treat TB infections in a manner that circumvents existing pathways of resistance. One strategy is to target the organism at the translational level by inhibiting vital modifications of RNA. One gene responsible for these modifications is the tRNA (guanosine-1)methyltransferase, trmD, which has been shown to be essential in several bacteria. The eukaryotic and bacterial m 1 G methyltransferases are structurally dissimilar, making this enzyme an ideal target for selective anti-TB agents. viii One strategy for TrmD inhibitor design is to target the catalytic center of the enzyme. Existing inhibitors such as Sinefungin exhibit poor selectivity due to the substrate’s role, SAM, as a universal methyl donor in many biological processes. Structure/activity relationships for inhibitory compounds are sparse, impeding the design of novel antimicrobials. Crystallographic data would identify molecular features unique to TrmD, and allow design of agents complimentary to the TrmD active site with minimal differential toxicity. Presently, no crystal structure for Mycobacterium tuberculosis TrmD