Phenotype studies of Orf135 CTPase from E. coli and complementation studies with RV1160 from M. tuberculosis

Abstract

We are studying the Nudix hydrolases from Mycobacterium tuberculosis as potential novel antibiotic targets. One such potential target is the CTPase Rv1160. Because it has a functional homolog in E. coli, Orf135 CTPase, we can study the phenotype of the orf135 E. coli knockout and carry out complementation studies with rv1160. CTP is a feedback inhibitor of pyrimidine biosynthesis, and a precursor to lipid biosynthesis, including cell membrane formation, thus Orf135 and Rv1160 may help regulate these pathways through degradation of CTP. The orf135 E. coli knockout is less susceptible to streptomycin, a phenotype consistent with a change in the cell membrane. The orf135 knockout mutant, containing a plasmid carrying rv1160, shows the same susceptibility to streptomycin as the wildtype E. coli, thus proving that Rv1160 complements Orf135. This research has been supported by an NIH AREA grant and an RIT College of Science summer fellowship.