Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressure

Abstract The final and rate-limiting enzyme in pyrimidine biosynthesis, cytidine triphosphate synthase (CTPS), is essential for the viability of Mycobacterium tuberculosis and other mycobacteria. Its product, cytidine triphosphate (CTP), is critical for RNA, DNA, lipid and cell wall synthesis, and i...

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Main Authors: Eric M. Lynch, Yao Lu, Jin Ho Park, Lin Shao, Justin M. Kollman, E. Hesper Rego
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-60847-6
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author Eric M. Lynch
Yao Lu
Jin Ho Park
Lin Shao
Justin M. Kollman
E. Hesper Rego
author_facet Eric M. Lynch
Yao Lu
Jin Ho Park
Lin Shao
Justin M. Kollman
E. Hesper Rego
author_sort Eric M. Lynch
collection DOAJ
description Abstract The final and rate-limiting enzyme in pyrimidine biosynthesis, cytidine triphosphate synthase (CTPS), is essential for the viability of Mycobacterium tuberculosis and other mycobacteria. Its product, cytidine triphosphate (CTP), is critical for RNA, DNA, lipid and cell wall synthesis, and is involved in chromosome segregation. In various organisms across the tree of life, CTPS assembles into higher-order filaments, leading us to hypothesize that M. tuberculosis CTPS (mtCTPS) also forms higher-order structures. Here, we show that mtCTPS does assemble into filaments but with an unusual architecture not seen in other organisms. Through a combination of structural, biochemical, and cellular techniques, we show that polymerization stabilizes the active conformation of the enzyme and resists product inhibition, potentially allowing for the highly localized production of CTP within the cell. Indeed, CTPS filaments localize near the CTP-dependent complex needed for chromosome segregation, and cells expressing mutant enzymes unable to polymerize are altered in their ability to robustly form this complex. Intriguingly, mutants that inhibit filament formation are under positive selection in clinical isolates of M. tuberculosis, pointing to a critical role needed to withstand pressures imposed by the host and/or antibiotics. Taken together, our data reveal an unexpected mechanism for the spatially organized production of a critical nucleotide in M. tuberculosis, which may represent a vulnerability of the pathogen that can be exploited with chemotherapy.
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spelling doaj-art-9bcd7131f47e464db98d3b08c193e3812025-08-20T03:37:37ZengNature PortfolioNature Communications2041-17232025-07-0116111410.1038/s41467-025-60847-6Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressureEric M. Lynch0Yao Lu1Jin Ho Park2Lin Shao3Justin M. Kollman4E. Hesper Rego5Department of Biochemistry, University of WashingtonDepartment of Microbial Pathogenesis, Yale University School of MedicineDepartment of Microbial Pathogenesis, Yale University School of MedicineCenter for Neurodevelopment and Plasticity, Wu Tsai Institute, Yale UniversityDepartment of Biochemistry, University of WashingtonDepartment of Microbial Pathogenesis, Yale University School of MedicineAbstract The final and rate-limiting enzyme in pyrimidine biosynthesis, cytidine triphosphate synthase (CTPS), is essential for the viability of Mycobacterium tuberculosis and other mycobacteria. Its product, cytidine triphosphate (CTP), is critical for RNA, DNA, lipid and cell wall synthesis, and is involved in chromosome segregation. In various organisms across the tree of life, CTPS assembles into higher-order filaments, leading us to hypothesize that M. tuberculosis CTPS (mtCTPS) also forms higher-order structures. Here, we show that mtCTPS does assemble into filaments but with an unusual architecture not seen in other organisms. Through a combination of structural, biochemical, and cellular techniques, we show that polymerization stabilizes the active conformation of the enzyme and resists product inhibition, potentially allowing for the highly localized production of CTP within the cell. Indeed, CTPS filaments localize near the CTP-dependent complex needed for chromosome segregation, and cells expressing mutant enzymes unable to polymerize are altered in their ability to robustly form this complex. Intriguingly, mutants that inhibit filament formation are under positive selection in clinical isolates of M. tuberculosis, pointing to a critical role needed to withstand pressures imposed by the host and/or antibiotics. Taken together, our data reveal an unexpected mechanism for the spatially organized production of a critical nucleotide in M. tuberculosis, which may represent a vulnerability of the pathogen that can be exploited with chemotherapy.https://doi.org/10.1038/s41467-025-60847-6
spellingShingle Eric M. Lynch
Yao Lu
Jin Ho Park
Lin Shao
Justin M. Kollman
E. Hesper Rego
Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressure
Nature Communications
title Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressure
title_full Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressure
title_fullStr Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressure
title_full_unstemmed Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressure
title_short Evolutionarily divergent Mycobacterium tuberculosis CTP synthase filaments are under selective pressure
title_sort evolutionarily divergent mycobacterium tuberculosis ctp synthase filaments are under selective pressure
url https://doi.org/10.1038/s41467-025-60847-6
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