Date of Award
College of Pharmacy and Health Sciences (COPHS)
Ph.D. in Pharmaceutical Science
Committee Member 1
Committee Member 2
Committee Member 3
Metalloprotease, Methionine Aminopeptidase, Mycobacterium tuberculosis, OJT008, Tuberculosis
Despite recent progress in the diagnosis of Tuberculosis (TB), the chemotherapeutic management of TB is still challenging. Mycobacterium tuberculosis (Mtb) is the etiological agent of TB, and TB is classified as the 13th leading cause of death globally [WHO 2021]. 558,000 people were reported to develop multi-drug resistant TB globally [WHO 2020]. Our research focuses on targeting Methionine Aminopeptidase (MetAP), an essential protein for the viability of Mtb. MetAP is a metalloprotease that catalyzes the removal of N-terminal methionine (NME) during translation of protein [Giglione et al., 2003]. This essential role of MetAPs makes this enzyme an auspicious target for the development of novel therapeutic agents for the treatment of TB. Mtb possesses two MetAP1 isoforms: MtMetAP1a and MtMetAP1c, which are vital for Mtb viability, hence a promising chemotherapeutic target for Mtb infection [Zhang et al., 2009; Olaleye et al., 2010; Griffin et al., 2011; Vanunu et al., 2019]. In our study, we cloned, overexpressed recombinant MtMetAP1c, and investigated the in vitro inhibitory effect of OJT008 on cobalt and nickel ion activated MtMetAP1c. The compound’s potency against replicating and multidrug-resistant (MDR) Mtb strains was also investigated. The induction of the overexpressed recombinant MtMetAP1c was optimized at hours with a final concentration of 1mM Isopropyl β-D-1-thiogalactopyranoside. The average yield for MtMetAP1c was 4.65 mg/L of Escherichia coli culture. A preliminary MtMetAP1c metal dependency screen showed optimum activation with nickel and cobalt ions at 100µM. The half-maximal inhibitory concentration (IC50) values of OJT008 against MtMetAP1c activated with CoCl2 and NiCl2 were in the micromolar range. Our in silico study showed OJT008 strongly binds to both metal activated MtMetAP1c, as evidenced by strong molecular interactions and higher binding score thereby corroborating our result. Thus, validating the pharmacophore’s metal specificity. The potency of OJT008 against both active and multidrug-resistant (MDR) Mtb was in the low micromolar concentrations, correlating well with our biochemical data on MtMetAP1c inhibition. These results suggest that OJT008 is a potential lead compound for the pre-clinical development of novel small molecules for the therapeutic management of TB.
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Onyenaka, Collins Chidi, "Discovery of OJT008 as a Novel Inhibitor of Mycobacterium tuberculosis" (2022). Dissertations (2016-Present). 18.