1
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Chu WT, Suo Z, Wang J. Three-metal ion mechanism of cross-linked and uncross-linked DNA polymerase β: A theoretical study. J Chem Phys 2024; 160:155101. [PMID: 38619457 DOI: 10.1063/5.0200109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/28/2024] [Indexed: 04/16/2024] Open
Abstract
In our recent publication, we have proposed a revised base excision repair pathway in which DNA polymerase β (Polβ) catalyzes Schiff base formation prior to the gap-filling DNA synthesis followed by β-elimination. In addition, the polymerase activity of Polβ employs the "three-metal ion mechanism" instead of the long-standing "two-metal ion mechanism" to catalyze phosphodiester bond formation based on the fact derived from time-resolved x-ray crystallography that a third Mg2+ was captured in the polymerase active site after the chemical reaction was initiated. In this study, we develop the models of the uncross-linked and cross-linked Polβ complexes and investigate the "three-metal ion mechanism" vs the "two-metal ion mechanism" by using the quantum mechanics/molecular mechanics molecular dynamics simulations. Our results suggest that the presence of the third Mg2+ ion stabilizes the reaction-state structures, strengthens correct nucleotide binding, and accelerates phosphodiester bond formation. The improved understanding of Polβ's catalytic mechanism provides valuable insights into DNA replication and damage repair.
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Affiliation(s)
- Wen-Ting Chu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Zucai Suo
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306, USA
| | - Jin Wang
- Department of Chemistry & Physics, State University of New York at Stony Brook, Stony Brook, New York 11794, USA
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2
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Debnath T, Cisneros GA. Investigation of the stability of D5SIC-DNAM-incorporated DNA duplex in Taq polymerase binary system: a systematic classical MD approach. Phys Chem Chem Phys 2024; 26:7287-7295. [PMID: 38353000 DOI: 10.1039/d3cp05571j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
DNA polymerases are fundamental enzymes that play a crucial role in processing DNA with high fidelity and accuracy ensuring the faithful transmission of genetic information. The recognition of unnatural base pairs (UBPs) by polymerases, enabling their replication, represents a significant and groundbreaking discovery with profound implications for genetic expansion. Romesberg et al. examined the impact of DNA containing 2,6-dimethyl-2H-isoquiniline-1-thione: D5SIC (DS) and 2-methoxy-3-methylnaphthalene: DNAM (DN) UBPs bound to T. aquaticus DNA polymerase (Taq) through crystal structure analysis. Here, we have used polarizable and nonpolarizable classical molecular dynamics (MD) simulations to investigate the structural aspects and stability of Taq in complex with a DNA duplex including a DS-DN pair in the terminal 3' and 5' positions. Our results suggest that the flexibility of UBP-incorporated DNA in the terminal position is arrested by the polymerase, thus preventing fraying and mispairing. Our investigation also reveals that the UBP remains in an intercalated conformation inside the active site, exhibiting two distinct orientations in agreement with experimental findings. Our analysis pinpoints particular residues responsible for favorable interactions with the UBP, with some relying on van der Waals interactions while other on Coulombic forces.
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Affiliation(s)
- Tanay Debnath
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA.
| | - G Andrés Cisneros
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA.
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA
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3
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Pan X, Van R, Pu J, Nam K, Mao Y, Shao Y. Free Energy Profile Decomposition Analysis for QM/MM Simulations of Enzymatic Reactions. J Chem Theory Comput 2023; 19:8234-8244. [PMID: 37943896 PMCID: PMC10835707 DOI: 10.1021/acs.jctc.3c00973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
In enzyme mechanistic studies and mutant design, it is highly desirable to know the individual residue contributions to the reaction free energy and barrier. In this work, we show that such free energy contributions from each residue can be readily obtained by postprocessing ab initio quantum mechanical molecular mechanical (ai-QM/MM) free energy simulation trajectories. Specifically, through a mean force integration along the minimum free energy pathway, one can obtain the electrostatic, polarization, and van der Waals contributions from each residue to the free energy barrier. Separately, a similar analysis procedure allows us to assess the contribution from different collective variables along the reaction coordinate. The chorismate mutase reaction is used to demonstrate the utilization of these two trajectory analysis tools.
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Affiliation(s)
- Xiaoliang Pan
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Richard Van
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
- Laboratory of Computational Biology, National, Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20824, United States
| | - Jingzhi Pu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Kwangho Nam
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Yuezhi Mao
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182, United States
| | - Yihan Shao
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
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4
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Maghsoud Y, Jayasinghe-Arachchige VM, Kumari P, Cisneros GA, Liu J. Leveraging QM/MM and Molecular Dynamics Simulations to Decipher the Reaction Mechanism of the Cas9 HNH Domain to Investigate Off-Target Effects. J Chem Inf Model 2023; 63:6834-6850. [PMID: 37877218 DOI: 10.1021/acs.jcim.3c01284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR) technology is an RNA-guided targeted genome-editing tool using Cas family proteins. Two magnesium-dependent nuclease domains of the Cas9 enzyme, termed HNH and RuvC, are responsible for cleaving the target DNA (t-DNA) and nontarget DNA strands, respectively. The HNH domain is believed to determine the DNA cleavage activity of both endonuclease domains and is sensitive to complementary RNA-DNA base pairing. However, the underlying molecular mechanisms of CRISPR-Cas9, by which it rebukes or accepts mismatches, are poorly understood. Thus, investigation of the structure and dynamics of the catalytic state of Cas9 with either matched or mismatched t-DNA can provide insights into improving its specificity by reducing off-target cleavages. Here, we focus on a recently discovered catalytic-active form of the Streptococcus pyogenes Cas9 (SpCas9) and employ classical molecular dynamics and coupled quantum mechanics/molecular mechanics simulations to study two possible mechanisms of t-DNA cleavage reaction catalyzed by the HNH domain. Moreover, by designing a mismatched t-DNA structure called MM5 (C to G at the fifth position from the protospacer adjacent motif region), the impact of single-guide RNA (sgRNA) and t-DNA complementarity on the catalysis process was investigated. Based on these simulations, our calculated binding affinities, minimum energy paths, and analysis of catalytically important residues provide atomic-level details of the differences between matched and mismatched cleavage reactions. In addition, several residues exhibit significant differences in their catalytic roles for the two studied systems, including K253, K263, R820, K896, and K913.
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Affiliation(s)
- Yazdan Maghsoud
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Vindi M Jayasinghe-Arachchige
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Pratibha Kumari
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - G Andrés Cisneros
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Jin Liu
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
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5
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Maghsoud Y, Dong C, Cisneros GA. Investigation of the Inhibition Mechanism of Xanthine Oxidoreductase by Oxipurinol: A Computational Study. J Chem Inf Model 2023; 63:4190-4206. [PMID: 37319436 PMCID: PMC10405278 DOI: 10.1021/acs.jcim.3c00624] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Xanthine oxidoreductase (XOR) is an enzyme found in various organisms. It converts hypoxanthine to xanthine and urate, which are crucial steps in purine elimination in humans. Elevated uric acid levels can lead to conditions like gout and hyperuricemia. Therefore, there is significant interest in developing drugs that target XOR for treating these conditions and other diseases. Oxipurinol, an analogue of xanthine, is a well-known inhibitor of XOR. Crystallographic studies have revealed that oxipurinol directly binds to the molybdenum cofactor (MoCo) in XOR. However, the precise details of the inhibition mechanism are still unclear, which would be valuable for designing more effective drugs with similar inhibitory functions. In this study, molecular dynamics and quantum mechanics/molecular mechanics calculations are employed to investigate the inhibition mechanism of XOR by oxipurinol. The study examines the structural and dynamic effects of oxipurinol on the pre-catalytic structure of the metabolite-bound system. Our results provide insights on the reaction mechanism catalyzed by the MoCo center in the active site, which aligns well with experimental findings. Furthermore, the results provide insights into the residues surrounding the active site and propose an alternative mechanism for developing alternative covalent inhibitors.
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Affiliation(s)
- Yazdan Maghsoud
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Chao Dong
- Department of Chemistry and Physics, The University of Texas Permian Basin, Odessa, Texas 79762, United States
| | - G Andrés Cisneros
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
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6
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Srivastava A, Idriss H, Homouz D. Structural Insights into Phosphorylation-Mediated Polymerase Function Loss for DNA Polymerase β Bound to Gapped DNA. Int J Mol Sci 2023; 24:ijms24108988. [PMID: 37240334 DOI: 10.3390/ijms24108988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
DNA polymerase β is a member of the X-family of DNA polymerases, playing a critical role in the base excision repair (BER) pathway in mammalian cells by implementing the nucleotide gap-filling step. In vitro phosphorylation of DNA polymerase β with PKC on S44 causes loss in the enzyme's DNA polymerase activity but not single-strand DNA binding. Although these studies have shown that single-stranded DNA binding is not affected by phosphorylation, the structural basis behind the mechanism underlying phosphorylation-induced activity loss remains poorly understood. Previous modeling studies suggested phosphorylation of S44 was sufficient to induce structural changes that impact the enzyme's polymerase function. However, the S44 phosphorylated-enzyme/DNA complex has not been modeled so far. To address this knowledge gap, we conducted atomistic molecular dynamics simulations of pol β complexed with gapped DNA. Our simulations, which used explicit solvent and lasted for microseconds, revealed that phosphorylation at the S44 site, in the presence of Mg ions, induced significant conformational changes in the enzyme. Specifically, these changes led to the transformation of the enzyme from a closed to an open structure. Additionally, our simulations identified phosphorylation-induced allosteric coupling between the inter-domain region, suggesting the existence of a putative allosteric site. Taken together, our results provide a mechanistic understanding of the conformational transition observed due to phosphorylation in DNA polymerase β interactions with gapped DNA. Our simulations shed light on the mechanisms of phosphorylation-induced activity loss in DNA polymerase β and reveal potential targets for the development of novel therapeutics aimed at mitigating the effects of this post-translational modification.
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Affiliation(s)
- Amit Srivastava
- Department of Physics, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - Haitham Idriss
- School of Public Health, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK
- Palestinian Neuroscience Initiative, Al-Quds University, Jerusalem 51000, Palestine
- Faculty of Health Sciences, Global University, Beirut 15-5085, Lebanon
| | - Dirar Homouz
- Department of Physics, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
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7
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Das CK, Gupta A, Nair NN. Probing the general base for DNA polymerization in telomerase: a molecular dynamics investigation. Phys Chem Chem Phys 2023; 25:14147-14157. [PMID: 37162325 DOI: 10.1039/d3cp00521f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Telomerase is an RNA-dependent DNA polymerase that plays a role in the maintenance of the 3' end of the eukaryotic chromosome, known as a telomere, by catalyzing the DNA polymerization reaction in cancer and embryonic stem cells. The detailed molecular details of the DNA polymerization by telomerase, especially the general base for deprotonating the terminal 3'-hydroxyl, which triggers the chemical reaction, remain elusive. We conducted a computational investigation using hybrid quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations to probe the detailed mechanism of the reaction. Our simulations started with the telomerase:RNA:DNA:dNTP ternary complex, and by using enhanced sampling QM/MM MD simulations, we probed the general base involved directly in the polymerization. We report the participation of an aspartate (Asp344) coordinated to Mg and an active site water molecule, jointly acting as a base during nucleic acid addition. The Asp344 residue remains transiently protonated during the course of the reaction, and later it deprotonates by transferring its proton to the water at the end of the reaction.
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Affiliation(s)
- Chandan Kumar Das
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
| | - Abhinav Gupta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
| | - Nisanth N Nair
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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8
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Maghsoud Y, Dong C, Cisneros GA. Computational Characterization of the Inhibition Mechanism of Xanthine Oxidoreductase by Topiroxostat. ACS Catal 2023; 13:6023-6043. [PMID: 37547543 PMCID: PMC10399974 DOI: 10.1021/acscatal.3c01245] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Xanthine oxidase (XO) is a member of the molybdopterin-containing enzyme family. It interconverts xanthine to uric acid as the last step of purine catabolism in the human body. The high uric acid concentration in the blood directly leads to human diseases like gout and hyperuricemia. Therefore, drugs that inhibit the biosynthesis of uric acid by human XO have been clinically used for many years to decrease the concentration of uric acid in the blood. In this study, the inhibition mechanism of XO and a new promising drug, topiroxostat (code: FYX-051), is investigated by employing molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) calculations. This drug has been reported to act as both a noncovalent and covalent inhibitor and undergoes a stepwise inhibition by all its hydroxylated metabolites, which include 2-hydroxy-FYX-051, dihydroxy-FYX-051, and trihydroxy-FYX-051. However, the detailed mechanism of inhibition of each metabolite remains elusive and can be useful for designing more effective drugs with similar inhibition functions. Hence, herein we present the computational investigation of the structural and dynamical effects of FYX-051 and the calculated reaction mechanism for all of the oxidation steps catalyzed by the molybdopterin center in the active site. Calculated results for the proposed reaction mechanisms for each metabolite's inhibition reaction in the enzyme's active site, binding affinities, and the noncovalent interactions with the surrounding amino acid residues are consistent with previously reported experimental findings. Analysis of the noncovalent interactions via energy decomposition analysis (EDA) and noncovalent interaction (NCI) techniques suggests that residues L648, K771, E802, R839, L873, R880, R912, F914, F1009, L1014, and A1079 can be used as key interacting residues for further hybrid-type inhibitor development.
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Affiliation(s)
- Yazdan Maghsoud
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Chao Dong
- Department of Chemistry and Physics, The University of Texas Permian Basin, Odessa, Texas 79762, United States
| | - G Andrés Cisneros
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States; Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
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9
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Geronimo I, Vidossich P, De Vivo M. On the Role of Molecular Conformation of the 8-Oxoguanine Lesion in Damaged DNA Processing by Polymerases. J Chem Inf Model 2023; 63:1521-1528. [PMID: 36825471 PMCID: PMC10015460 DOI: 10.1021/acs.jcim.2c01430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
A common and insidious DNA damage is 8-oxoguanine (8OG), bypassed with low catalytic efficiency and high error frequency by polymerases (Pols) during DNA replication. This is a fundamental process with far-reaching implications in cell function and diseases. However, the molecular determinants of how 8OG exactly affects the catalytic efficiency of Pols remain largely unclear. By examining ternary deoxycytidine triphosphate/DNA/Pol complexes containing the 8OG damage, we found that 8OG consistently adopts different conformations when bound to Pols, compared to when in isolated DNA. Equilibrium molecular dynamics and metadynamics free energy calculations quantified that 8OG is in the lowest energy conformation in isolated DNA. In contrast, 8OG adopts high-energy conformations often characterized by intramolecular steric repulsion when bound to Pols. We show that the 8OG conformation can be regulated by mutating Pol residues interacting with the 8OG phosphate group. These findings propose the 8OG conformation as a factor in Pol-mediated processing of damaged DNA.
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Affiliation(s)
- Inacrist Geronimo
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Pietro Vidossich
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Marco De Vivo
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
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10
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Srivastava A, Idriss H, Taha K, Lee S, Homouz D. Phosphorylation Induced Conformational Transitions in DNA Polymerase β. Front Mol Biosci 2022; 9:900771. [PMID: 35769908 PMCID: PMC9234555 DOI: 10.3389/fmolb.2022.900771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
DNA polymerase β (pol β) is a member of the X- family of DNA polymerases that catalyze the distributive addition of nucleoside triphosphates during base excision DNA repair. Previous studies showed that the enzyme was phosphorylated in vitro with PKC at two serines (44 and 55), causing loss of DNA polymerase activity but not DNA binding. In this work, we have investigated the phosphorylation-induced conformational changes in DNA polymerase β in the presence of Mg ions. We report a comprehensive atomic resolution study of wild type and phosphorylated DNA polymerase using molecular dynamics (MD) simulations. The results are examined via novel methods of internal dynamics and energetics analysis to reveal the underlying mechanism of conformational transitions observed in DNA pol β. The results show drastic conformational changes in the structure of DNA polymerase β due to S44 phosphorylation. Phosphorylation-induced conformational changes transform the enzyme from a closed to an open structure. The dynamic cross-correlation shows that phosphorylation enhances the correlated motions between the different domains. Centrality network analysis reveals that the S44 phosphorylation causes structural rearrangements and modulates the information pathway between the Lyase domain and base pair binding domain. Further analysis of our simulations reveals that a critical hydrogen bond (between S44 and E335) disruption and the formation of three additional salt bridges are potential drivers of these conformational changes. In addition, we found that two of these additional salt bridges form in the presence of Mg ions on the active sites of the enzyme. These results agree with our previous study of DNA pol β S44 phosphorylation without Mg ions which predicted the deactivation of DNA pol β. However, the phase space of structural transitions induced by S44 phosphorylation is much richer in the presence of Mg ions.
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Affiliation(s)
- Amit Srivastava
- Department of Physics, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Haitham Idriss
- Palestinian Neuroscience Initiative, AlQuds University, Jerusalem, Palestine
- School of Public Health, Imperial College of Science, Technology and Medicine, London, United Kingdom
| | - Kamal Taha
- Department of Electrical Engineering and Computer Science, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Sungmun Lee
- Biomedical Engineering Department, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Dirar Homouz
- Department of Physics, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Department of Physics, University of Houston, Houston, TX, United States
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States
- *Correspondence: Dirar Homouz,
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11
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Wilson KA, Jeong YER, Wetmore SD. Multiscale computational investigations of the translesion synthesis bypass of tobacco-derived DNA adducts: critical insights that complement experimental biochemical studies. Phys Chem Chem Phys 2022; 24:10667-10683. [PMID: 35502640 DOI: 10.1039/d2cp00481j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Among the numerous agents that damage DNA, tobacco products remain one of the most lethal and result in the most diverse set of DNA lesions. This perspective aims to provide an overview of computational work conducted to complement experimental biochemical studies on the mutagenicity of adducts derived from the most potent tobacco carcinogen, namely 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (nicotine-derived nitrosaminoketone or NNK). Lesions ranging from the smallest methylated thymine derivatives to the larger, flexible pyridyloxobutyl (POB) guanine adducts are considered. Insights are obtained from density functional theory (DFT) calculations and molecular dynamics (MD) simulations into the damaged nucleobase and nucleoside structures, the accommodation of the lesions in the active site of key human polymerases, the intrinsic base pairing potentials of the adducts, and dNTP incorporation opposite the lesions. Overall, the computational data provide atomic level information that can rationalize the differential mutagenic properties of tobacco-derived lesions and uncover important insights into the impact of adduct size, nucleobase, position, and chemical composition of the bulky moiety.
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Affiliation(s)
- Katie A Wilson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute (ARRTI) and Southern Alberta Genome Sciences Center (SAGSC), University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
| | - Ye Eun Rebecca Jeong
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute (ARRTI) and Southern Alberta Genome Sciences Center (SAGSC), University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute (ARRTI) and Southern Alberta Genome Sciences Center (SAGSC), University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
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12
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Hix MA, Leddin EM, Cisneros GA. Combining Evolutionary Conservation and Quantum Topological Analyses To Determine Quantum Mechanics Subsystems for Biomolecular Quantum Mechanics/Molecular Mechanics Simulations. J Chem Theory Comput 2021; 17:4524-4537. [PMID: 34087064 PMCID: PMC8477969 DOI: 10.1021/acs.jctc.1c00313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Selection of residues and other molecular fragments for inclusion in the quantum mechanics (QM) region for QM/molecular mechanics (MM) simulations is an important step for these calculations. Here, we present an approach that combines protein sequence/structure evolution and electron localization function (ELF) analyses. The combination of these two analyses allows the determination of whether a residue needs to be included in the QM subsystem or can be represented by the MM environment. We have applied this approach on two systems previously investigated by QM/MM simulations, 4-oxalocrotonate tautomerase (4OT) and ten-eleven translocation-2 (TET2), that provide examples where fragments may or may not need to be included in the QM subsystem. Subsequently, we present the use of this approach to determine the appropriate QM subsystem to calculate the minimum energy path (MEP) for the reaction catalyzed by human DNA polymerase λ (Polλ) with a third cation in the active site. Our results suggest that the combination of protein evolutionary and ELF analyses provides insights into residue/molecular fragment selection for QM/MM simulations.
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Affiliation(s)
- Mark A Hix
- Department of Chemistry, University of North Texas, Denton, Texas 76201, United States
| | - Emmett M Leddin
- Department of Chemistry, University of North Texas, Denton, Texas 76201, United States
| | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, Texas 76201, United States
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13
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Ouaray Z, Benner SA, Georgiadis MM, Richards NGJ. Building better polymerases: Engineering the replication of expanded genetic alphabets. J Biol Chem 2020; 295:17046-17059. [PMID: 33004440 PMCID: PMC7863901 DOI: 10.1074/jbc.rev120.013745] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 09/30/2020] [Indexed: 11/30/2022] Open
Abstract
DNA polymerases are today used throughout scientific research, biotechnology, and medicine, in part for their ability to interact with unnatural forms of DNA created by synthetic biologists. Here especially, natural DNA polymerases often do not have the "performance specifications" needed for transformative technologies. This creates a need for science-guided rational (or semi-rational) engineering to identify variants that replicate unnatural base pairs (UBPs), unnatural backbones, tags, or other evolutionarily novel features of unnatural DNA. In this review, we provide a brief overview of the chemistry and properties of replicative DNA polymerases and their evolved variants, focusing on the Klenow fragment of Taq DNA polymerase (Klentaq). We describe comparative structural, enzymatic, and molecular dynamics studies of WT and Klentaq variants, complexed with natural or noncanonical substrates. Combining these methods provides insight into how specific amino acid substitutions distant from the active site in a Klentaq DNA polymerase variant (ZP Klentaq) contribute to its ability to replicate UBPs with improved efficiency compared with Klentaq. This approach can therefore serve to guide any future rational engineering of replicative DNA polymerases.
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Affiliation(s)
- Zahra Ouaray
- School of Chemistry, Cardiff University, Park Place, Cardiff, United Kingdom
| | - Steven A Benner
- Foundation for Applied Molecular Evolution, Alachua, Florida, USA
| | - Millie M Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
| | - Nigel G J Richards
- School of Chemistry, Cardiff University, Park Place, Cardiff, United Kingdom; Foundation for Applied Molecular Evolution, Alachua, Florida, USA.
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14
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Kathuria P, Singh P, Sharma P, Wetmore SD. Replication of the Aristolochic Acid I Adenine Adduct (ALI-N6-A) by a Model Translesion Synthesis DNA Polymerase: Structural Insights on the Induction of Transversion Mutations from Molecular Dynamics Simulations. Chem Res Toxicol 2020; 33:2573-2583. [DOI: 10.1021/acs.chemrestox.0c00183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Preetleen Kathuria
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Prebhleen Singh
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
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15
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Berta D, Buigues PJ, Badaoui M, Rosta E. Cations in motion: QM/MM studies of the dynamic and electrostatic roles of H + and Mg 2+ ions in enzyme reactions. Curr Opin Struct Biol 2020; 61:198-206. [PMID: 32065923 DOI: 10.1016/j.sbi.2020.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 12/17/2022]
Abstract
Here we discuss current trends in the simulations of enzymatic reactions focusing on phosphate catalysis. The mechanistic details of the proton transfers coupled to the phosphate cleavage is one of the key challenges in QM/MM calculations of these and other enzyme catalyzed reactions. The lack of experimental information offers both an opportunity for computations as well as often unresolved controversies. We discuss the example of small GTPases including the important human Ras protein. The high dimensionality and chemical complexity of these reactions demand carefully chosen computational techniques both in terms of the underlying quantum chemical theory and the sampling of the conformational ensemble. We also point out the important role of Mg2+ ions, and recent advances in their transient involvement in the catalytic mechanisms.
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Affiliation(s)
- Dénes Berta
- Department of Chemistry, King's College London, London, SE1 1DB, United Kingdom
| | - Pedro J Buigues
- Department of Chemistry, King's College London, London, SE1 1DB, United Kingdom
| | - Magd Badaoui
- Department of Chemistry, King's College London, London, SE1 1DB, United Kingdom
| | - Edina Rosta
- Department of Chemistry, King's College London, London, SE1 1DB, United Kingdom.
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16
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Bhutani P, Nikkel DJ, Wilson KA, Wetmore SD. Computational Insight into the Differential Mutagenic Patterns of O-Methylthymine Lesions. Chem Res Toxicol 2019; 32:2107-2117. [DOI: 10.1021/acs.chemrestox.9b00291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Priya Bhutani
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta T1K 3M4, Canada
| | - Dylan J. Nikkel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta T1K 3M4, Canada
| | - Katie A. Wilson
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta T1K 3M4, Canada
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17
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Wilson KA, Fernandes PA, Ramos MJ, Wetmore SD. Exploring the Identity of the General Base for a DNA Polymerase Catalyzed Reaction Using QM/MM: The Case Study of Human Translesion Synthesis Polymerase η. ACS Catal 2019. [DOI: 10.1021/acscatal.8b04889] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Katie A. Wilson
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4 Canada
| | - Pedro A. Fernandes
- UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Maria J. Ramos
- UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4 Canada
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18
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Gahlon HL, Walker AR, Cisneros GA, Lamers MH, Rueda DS. Reduced structural flexibility for an exonuclease deficient DNA polymerase III mutant. Phys Chem Chem Phys 2018; 20:26892-26902. [PMID: 30345999 PMCID: PMC6278910 DOI: 10.1039/c8cp04112a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
DNA synthesis, carried out by DNA polymerases, requires balancing speed and accuracy for faithful replication of the genome. High fidelity DNA polymerases contain a 3'-5' exonuclease domain that can remove misincorporated nucleotides on the 3' end of the primer strand, a process called proofreading. The E. coli replicative polymerase, DNA polymerase III, has spatially separated (∼55 Å apart) polymerase and exonuclease subunits. Here, we report on the dynamics of E. coli DNA polymerase III proofreading in the presence of its processivity factor, the β2-sliding clamp, at varying base pair termini using single-molecule FRET. We find that the binding kinetics do not depend on the base identity at the termini, indicating a tolerance for DNA mismatches. Further, our single-molecule data and MD simulations show two previously unobserved features: (1) DNA Polymerase III is a highly dynamic protein that adopts multiple conformational states while bound to DNA with matched or mismatched ends, and (2) an exonuclease-deficient DNA polymerase III has reduced conformational flexibility. Overall, our single-molecule experiments provide high time-resolution insight into a mechanism that ensures high fidelity DNA replication to maintain genome integrity.
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Affiliation(s)
- Hailey L Gahlon
- Department of Medicine, Molecular Virology, Imperial College London, Du Cane Road, London W12 0NN, UK.
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19
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Affiliation(s)
- Vito Genna
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Elisa Donati
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Marco De Vivo
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
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20
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Stevens DR, Hammes-Schiffer S. Exploring the Role of the Third Active Site Metal Ion in DNA Polymerase η with QM/MM Free Energy Simulations. J Am Chem Soc 2018; 140:8965-8969. [PMID: 29932331 DOI: 10.1021/jacs.8b05177] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The enzyme human DNA polymerase η (Pol η) is critical for bypassing lesions during DNA replication. In addition to the two Mg2+ ions aligning the active site, experiments suggest that a third Mg2+ ion could play an essential catalytic role. Herein the role of this third metal ion is investigated with quantum mechanical/molecular mechanical (QM/MM) free energy simulations of the phosphoryl transfer reaction and a proposed self-activating proton transfer from the incoming nucleotide to the pyrophosphate leaving group. The simulations with only two metal ions in the active site support a sequential mechanism, with phosphoryl transfer followed by relatively fast proton transfer. The simulations with three metal ions in the active site suggest that the third metal ion may play a catalytic role through electrostatic interactions with the leaving group. These electrostatic interactions stabilize the product, making the phosphoryl transfer reaction more thermodynamically favorable with a lower free energy barrier relative to the activated state corresponding to the deprotonated 3'OH nucleophile, and also inhibit the subsequent proton transfer. The possibility that Mg2+-bound hydroxide acts as the base deprotonating the 3'OH nucleophile is also explored.
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Affiliation(s)
- David R Stevens
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , Connecticut 06520 , United States
| | - Sharon Hammes-Schiffer
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , Connecticut 06520 , United States
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