Date of Award
5-2026
Document Type
Thesis
Degree Name
Master of Science (MS)
College/School
College of Science and Mathematics
Department/Program
Chemistry and Biochemistry
Thesis Sponsor/Dissertation Chair/Project Chair
Nina Goodey
Committee Member
David Konas
Committee Member
David Rotella
Abstract
M. tuberculosis (Mt) is the bacterium that causes one of the oldest known human diseases, tuberculosis (TB). The efficacy of first line antituberculosis drugs has declined due to the increasing presence of multidrug-resistant Mt strains, highlighting the urgent need for new therapeutic strategies (Lenaerts, et al., 2008; Shen, et al., 2009). Indole-3-glycerol phosphate synthase (IGPS) from Mt (MtIGPS) has been proposed as a potential drug target due to its role in catalyzing the fourth step in tryptophan biosynthesis, a pathway essential for Mt survival. MtIGPS converts the substrate 1-(o-carboxyphenylamino)-1-deoxyribulose-5-phosphate (CdRP) into the product indole-3-glycerol phosphate (IGP) through a proposed three-step mechanism involving cyclization, decarboxylation, and dehydration. MtIGPS was expressed with an N-terminal His-tag and purified using Ni-NTA affinity chromatography. To investigate the rate-determining step of MtIGPS catalysis, solvent deuterium kinetic isotope effect (SDKIE) and solvent viscosity effect (SVE) experiments were performed for wildtype MtIGPS and active site mutation E57D. Wildtype MtIGPS exhibited a 2-fold decrease in k꜀ₐₜ and kₒbₛ in D₂O and no change with increased the E57D mutant showed increased catalytic rates in D₂O and with increased solvent viscosity, suggesting that these substitutions alter the rate-determining step of MtIGPS catalysis. By integrating SDKIE and SVE data, this work provides insight into how active-site residues influence the rate-determining step in MtIGPS, which support future MtIGPS inhibitor development.
File Format
Recommended Citation
Montero, Crystal, "Investigating the rate-limiting step in M. tuberculosis indole-3-glycerol phosphate synthase, a potential Tuberculosis drug target" (2026). Theses, Dissertations and Culminating Projects. 1684.
https://digitalcommons.montclair.edu/etd/1684