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dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis

[Image: see text] Thymidylate synthase is an enzyme that catalyzes deoxythymidine monophosphate (dTMP) synthesis from substrate deoxyuridine monophosphate (dUMP). Thymidylate synthase of Mycobacterium tuberculosis (MtbThyX) is structurally distinct from its human analogue human thymidylate synthase...

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Autores principales: Gaurav, Kumar, Adhikary, Tiasha, Satpati, Priyadarshi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2020
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7376888/
https://www.ncbi.nlm.nih.gov/pubmed/32715203
http://dx.doi.org/10.1021/acsomega.0c01224
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author Gaurav, Kumar
Adhikary, Tiasha
Satpati, Priyadarshi
author_facet Gaurav, Kumar
Adhikary, Tiasha
Satpati, Priyadarshi
author_sort Gaurav, Kumar
collection PubMed
description [Image: see text] Thymidylate synthase is an enzyme that catalyzes deoxythymidine monophosphate (dTMP) synthesis from substrate deoxyuridine monophosphate (dUMP). Thymidylate synthase of Mycobacterium tuberculosis (MtbThyX) is structurally distinct from its human analogue human thymidylate synthase (hThyA), thus drawing attention as an attractive drug target for combating tuberculosis. Fluorodeoxyuridylate (F-dUMP) is a successful inhibitor of both MtbThyX and hThyA, thus limited by poor selectivity. Understanding the dynamics and energetics associated with substrate/inhibitor binding to thymidylate synthase in atomic details remains a fundamental unsolved problem, which is necessary for a new selective inhibitor design. Structural studies of MtbThyX and hThyA bound substrate/inhibitor complexes not only revealed the extensive specific interaction network between protein and ligands but also opened up the possibility of directly computing the energetics of the substrate versus inhibitor recognition. Using experimentally determined structures as a template, we report extensive computer simulations (∼4.5 μs) that allow us to quantitatively estimate ligand selectivity (dUMP vs F-dUMP) by MtbThyX and hThyA. We show that MtbThyX prefers deprotonated dUMP (enolate form) as the substrate, whereas hThyA binds to the keto form of dUMP. Computed energetics clearly show that MtbThyX is less selective between dUMP and F-dUMP, favoring the latter, relative to hThyA. The simulations reveal the role of tyrosine at position 135 (Y135) of hThyA in amplifying the selectivity. The protonation state of the pyrimidine base of the ligand (i.e., keto or enolate) seems to have no role in MtbThyX ligand selectivity. A molecular gate (consists of Y108, K165, H203, and a water molecule) restricts water accessibility and offers a desolvated dry ligand-binding pocket for MtbThyX. The ligand-binding pocket of hThyA is relatively wet and exposed to bulk water.
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spelling pubmed-73768882020-07-24 dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis Gaurav, Kumar Adhikary, Tiasha Satpati, Priyadarshi ACS Omega [Image: see text] Thymidylate synthase is an enzyme that catalyzes deoxythymidine monophosphate (dTMP) synthesis from substrate deoxyuridine monophosphate (dUMP). Thymidylate synthase of Mycobacterium tuberculosis (MtbThyX) is structurally distinct from its human analogue human thymidylate synthase (hThyA), thus drawing attention as an attractive drug target for combating tuberculosis. Fluorodeoxyuridylate (F-dUMP) is a successful inhibitor of both MtbThyX and hThyA, thus limited by poor selectivity. Understanding the dynamics and energetics associated with substrate/inhibitor binding to thymidylate synthase in atomic details remains a fundamental unsolved problem, which is necessary for a new selective inhibitor design. Structural studies of MtbThyX and hThyA bound substrate/inhibitor complexes not only revealed the extensive specific interaction network between protein and ligands but also opened up the possibility of directly computing the energetics of the substrate versus inhibitor recognition. Using experimentally determined structures as a template, we report extensive computer simulations (∼4.5 μs) that allow us to quantitatively estimate ligand selectivity (dUMP vs F-dUMP) by MtbThyX and hThyA. We show that MtbThyX prefers deprotonated dUMP (enolate form) as the substrate, whereas hThyA binds to the keto form of dUMP. Computed energetics clearly show that MtbThyX is less selective between dUMP and F-dUMP, favoring the latter, relative to hThyA. The simulations reveal the role of tyrosine at position 135 (Y135) of hThyA in amplifying the selectivity. The protonation state of the pyrimidine base of the ligand (i.e., keto or enolate) seems to have no role in MtbThyX ligand selectivity. A molecular gate (consists of Y108, K165, H203, and a water molecule) restricts water accessibility and offers a desolvated dry ligand-binding pocket for MtbThyX. The ligand-binding pocket of hThyA is relatively wet and exposed to bulk water. American Chemical Society 2020-07-06 /pmc/articles/PMC7376888/ /pubmed/32715203 http://dx.doi.org/10.1021/acsomega.0c01224 Text en Copyright © 2020 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Gaurav, Kumar
Adhikary, Tiasha
Satpati, Priyadarshi
dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis
title dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis
title_full dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis
title_fullStr dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis
title_full_unstemmed dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis
title_short dUMP/F-dUMP Binding to Thymidylate Synthase: Human Versus Mycobacterium tuberculosis
title_sort dump/f-dump binding to thymidylate synthase: human versus mycobacterium tuberculosis
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7376888/
https://www.ncbi.nlm.nih.gov/pubmed/32715203
http://dx.doi.org/10.1021/acsomega.0c01224
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