Investigating the Roles of Active Site Residues in Mycobacterium tuberculosis Indole-3-glycerol Phosphate Synthase, a Potential Target for Antitubercular Agents
David W. Konas, Sarah Cho, Oshane D. Thomas, Maryum M. Bhatti, Katherine Leon Hernandez, Cinthya Moran, Hedda Booter, Thomas Candela, Joseph Lacap, Paige McFadden, Savannah van den Berg, Alyssa M. Welter, Ashley Peralta, Cheryl A. Janson, Jaclyn Catalano and Nina M. Goodey*,
{"title":"Investigating the Roles of Active Site Residues in Mycobacterium tuberculosis Indole-3-glycerol Phosphate Synthase, a Potential Target for Antitubercular Agents","authors":"David W. Konas, Sarah Cho, Oshane D. Thomas, Maryum M. Bhatti, Katherine Leon Hernandez, Cinthya Moran, Hedda Booter, Thomas Candela, Joseph Lacap, Paige McFadden, Savannah van den Berg, Alyssa M. Welter, Ashley Peralta, Cheryl A. Janson, Jaclyn Catalano and Nina M. Goodey*, ","doi":"10.1021/acsbiomedchemau.3c00029","DOIUrl":null,"url":null,"abstract":"<p ><i>Mycobacterium tuberculosis</i> drug resistance is emerging and new drug targets are needed. Tryptophan biosynthesis is necessary for <i>M. tuberculosis</i> replication and virulence. Indole-3-glycerol phosphate synthase (IGPS) catalyzes a step in <i>M. tuberculosis</i> tryptophan biosynthesis and has been suggested as a potential anti-infective target, but our understanding of this enzyme is limited. To aid in inhibitor design and gain a greater mechanistic picture of this enzyme, there is a need to understand the roles of active site amino acids in ligand binding and catalysis. In this work, we explored the roles of conserved active site amino acids Glu57, Lys59, Lys119, Glu168, and Glu219. Mutation of each to Ala results in loss of all detectable activity. The Glu57Gln, Lys59Arg, Lys119Arg, Glu168Gln, and Glu219Asp mutations result in large activity losses, while Glu219Gln has enhanced activity. Analysis of the enzymatic data yields the following main conclusions: (A) Lys119 is the likely catalytic acid in the CdRP ring closure step. (B) Glu168 stabilizes a charged reaction intermediate and may also be the catalytic base. (C) Glu57, Glu219, and Lys119 form a closely arranged triad in which Glu57 and Glu219 modulate the p<i>K</i><sub>a</sub> of Lys119, and thus overall activity. This increased understanding of inter- and intramolecular interactions and demonstration of the highly coordinated nature of the <i>M. tuberculosis</i> IGPS active site provide new mechanistic information and guidance for future work with this potential new drug target.</p>","PeriodicalId":29802,"journal":{"name":"ACS Bio & Med Chem Au","volume":"3 5","pages":"438–447"},"PeriodicalIF":3.8000,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsbiomedchemau.3c00029","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Bio & Med Chem Au","FirstCategoryId":"1085","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acsbiomedchemau.3c00029","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Mycobacterium tuberculosis drug resistance is emerging and new drug targets are needed. Tryptophan biosynthesis is necessary for M. tuberculosis replication and virulence. Indole-3-glycerol phosphate synthase (IGPS) catalyzes a step in M. tuberculosis tryptophan biosynthesis and has been suggested as a potential anti-infective target, but our understanding of this enzyme is limited. To aid in inhibitor design and gain a greater mechanistic picture of this enzyme, there is a need to understand the roles of active site amino acids in ligand binding and catalysis. In this work, we explored the roles of conserved active site amino acids Glu57, Lys59, Lys119, Glu168, and Glu219. Mutation of each to Ala results in loss of all detectable activity. The Glu57Gln, Lys59Arg, Lys119Arg, Glu168Gln, and Glu219Asp mutations result in large activity losses, while Glu219Gln has enhanced activity. Analysis of the enzymatic data yields the following main conclusions: (A) Lys119 is the likely catalytic acid in the CdRP ring closure step. (B) Glu168 stabilizes a charged reaction intermediate and may also be the catalytic base. (C) Glu57, Glu219, and Lys119 form a closely arranged triad in which Glu57 and Glu219 modulate the pKa of Lys119, and thus overall activity. This increased understanding of inter- and intramolecular interactions and demonstration of the highly coordinated nature of the M. tuberculosis IGPS active site provide new mechanistic information and guidance for future work with this potential new drug target.
期刊介绍:
ACS Bio & Med Chem Au is a broad scope open access journal which publishes short letters comprehensive articles reviews and perspectives in all aspects of biological and medicinal chemistry. Studies providing fundamental insights or describing novel syntheses as well as clinical or other applications-based work are welcomed.This broad scope includes experimental and theoretical studies on the chemical physical mechanistic and/or structural basis of biological or cell function in all domains of life. It encompasses the fields of chemical biology synthetic biology disease biology cell biology agriculture and food natural products research nucleic acid biology neuroscience structural biology and biophysics.The journal publishes studies that pertain to a broad range of medicinal chemistry including compound design and optimization biological evaluation molecular mechanistic understanding of drug delivery and drug delivery systems imaging agents and pharmacology and translational science of both small and large bioactive molecules. Novel computational cheminformatics and structural studies for the identification (or structure-activity relationship analysis) of bioactive molecules ligands and their targets are also welcome. The journal will consider computational studies applying established computational methods but only in combination with novel and original experimental data (e.g. in cases where new compounds have been designed and tested).Also included in the scope of the journal are articles relating to infectious diseases research on pathogens host-pathogen interactions therapeutics diagnostics vaccines drug-delivery systems and other biomedical technology development pertaining to infectious diseases.