1
|
Pushkaran AC, Arabi AA. A review on point mutations via proton transfer in DNA base pairs in the absence and presence of electric fields. Int J Biol Macromol 2024:134051. [PMID: 39069038 DOI: 10.1016/j.ijbiomac.2024.134051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 07/12/2024] [Accepted: 07/18/2024] [Indexed: 07/30/2024]
Abstract
This is a comprehensive review that focuses on spontaneous mutations that may occur during DNA replication, the fundamental process responsible for transferring genetic information. In 1963, Löwdin postulated that these mutations are primarily a result of proton transfer reactions within the hydrogen-bonded DNA base pairs. The single and double proton transfer reactions within the base pairs result in zwitterions and rare tautomers, respectively. For persistent mutations, these products must be generated at high rates and should be thermodynamically stable. This review covers the proton transfer reactions studied experimentally and computationally. The review also examines the influence of externally applied electric fields on the thermodynamics and kinetics of proton transfer reactions within DNA base pairs, and their biological implications.
Collapse
Affiliation(s)
- Anju Choorakottayil Pushkaran
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, P.O. Box: 15551, United Arab Emirates
| | - Alya A Arabi
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, P.O. Box: 15551, United Arab Emirates.
| |
Collapse
|
2
|
Tao Y, Giese TJ, York DM. Electronic and Nuclear Quantum Effects on Proton Transfer Reactions of Guanine-Thymine (G-T) Mispairs Using Combined Quantum Mechanical/Molecular Mechanical and Machine Learning Potentials. Molecules 2024; 29:2703. [PMID: 38893576 PMCID: PMC11173453 DOI: 10.3390/molecules29112703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
Rare tautomeric forms of nucleobases can lead to Watson-Crick-like (WC-like) mispairs in DNA, but the process of proton transfer is fast and difficult to detect experimentally. NMR studies show evidence for the existence of short-time WC-like guanine-thymine (G-T) mispairs; however, the mechanism of proton transfer and the degree to which nuclear quantum effects play a role are unclear. We use a B-DNA helix exhibiting a wGT mispair as a model system to study tautomerization reactions. We perform ab initio (PBE0/6-31G*) quantum mechanical/molecular mechanical (QM/MM) simulations to examine the free energy surface for tautomerization. We demonstrate that while the ab initio QM/MM simulations are accurate, considerable sampling is required to achieve high precision in the free energy barriers. To address this problem, we develop a QM/MM machine learning potential correction (QM/MM-ΔMLP) that is able to improve the computational efficiency, greatly extend the accessible time scales of the simulations, and enable practical application of path integral molecular dynamics to examine nuclear quantum effects. We find that the inclusion of nuclear quantum effects has only a modest effect on the mechanistic pathway but leads to a considerable lowering of the free energy barrier for the GT*⇌G*T equilibrium. Our results enable a rationalization of observed experimental data and the prediction of populations of rare tautomeric forms of nucleobases and rates of their interconversion in B-DNA.
Collapse
|
3
|
Pietruszka M, Marzec M. Proton-polarized states in DNA. Biosystems 2024; 237:105125. [PMID: 38331379 DOI: 10.1016/j.biosystems.2024.105125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 02/10/2024]
Abstract
We observed signatures of a phase transition in the double-stranded DNA fragment of known length and sequences using a non-invasive semiconductor-electrolyte interface technique and statistical physics methods. Observations revealed a coherence peak in the electromotive force and a significant decline in calculated dynamic entropy at a critical temperature and pH. This behavior may arise from the dynamic interaction of proton (H+) pairs with opposite momentum and spin, carrying a charge q=2+ under critical conditions.
Collapse
Affiliation(s)
- Mariusz Pietruszka
- University of Silesia, Faculty of Natural Sciences, Institute of Biology, Biotechnology, and Environmental Protection, 40-032 Katowice, Poland.
| | - Marek Marzec
- University of Silesia, Faculty of Natural Sciences, Institute of Biology, Biotechnology, and Environmental Protection, 40-032 Katowice, Poland
| |
Collapse
|
4
|
Samir S. Human DNA Mutations and their Impact on Genetic Disorders. Recent Pat Biotechnol 2024; 18:288-315. [PMID: 37936448 DOI: 10.2174/0118722083255081231020055309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 07/25/2023] [Accepted: 09/18/2023] [Indexed: 11/09/2023]
Abstract
DNA is a remarkably precise medium for copying and storing biological information. It serves as a design for cellular machinery that permits cells, organs, and even whole organisms to work. The fidelity of DNA replication results from the action of hundreds of genes involved in proofreading and damage repair. All human cells can acquire genetic changes in their DNA all over life. Genetic mutations are changes to the DNA sequence that happen during cell division when the cells make copies of themselves. Mutations in the DNA can cause genetic illnesses such as cancer, or they could help humans better adapt to their environment over time. The endogenous reactive metabolites, therapeutic medicines, and an excess of environmental mutagens, such as UV rays all continuously damage DNA, compromising its integrity. One or more chromosomal alterations and point mutations at a single site (monogenic mutation) including deletions, duplications, and inversions illustrate such DNA mutations. Genetic conditions can occur when an altered gene is inherited from parents, which increases the risk of developing that particular condition, or some gene alterations can happen randomly. Moreover, symptoms of genetic conditions depend on which gene has a mutation. There are many different diseases and conditions caused by mutations. Some of the most common genetic conditions are Alzheimer's disease, some cancers, cystic fibrosis, Down syndrome, and sickle cell disease. Interestingly, scientists find that DNA mutations are more common than formerly thought. This review outlines the main DNA mutations that occur along the human genome and their influence on human health. The subject of patents pertaining to DNA mutations and genetic disorders has been brought up.
Collapse
Affiliation(s)
- Safia Samir
- Department of Biochemistry and Molecular Biology, Theodor Bilharz Research Institute, Giza, Egypt
| |
Collapse
|
5
|
Winokan M, Slocombe L, Al-Khalili J, Sacchi M. Multiscale simulations reveal the role of PcrA helicase in protecting against spontaneous point mutations in DNA. Sci Rep 2023; 13:21749. [PMID: 38065963 PMCID: PMC10709646 DOI: 10.1038/s41598-023-48119-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Proton transfer across hydrogen bonds in DNA can produce non-canonical nucleobase dimers and is a possible source of single-point mutations when these forms mismatch under replication. Previous computational studies have revealed this process to be energetically feasible for the guanine-cytosine (GC) base pair, but the tautomeric product (G[Formula: see text]C[Formula: see text]) is short-lived. In this work we reveal, for the first time, the direct effect of the replisome enzymes on proton transfer, rectifying the shortcomings of existing models. Multi-scale quantum mechanical/molecular dynamics (QM/MM) simulations reveal the effect of the bacterial PcrA Helicase on the double proton transfer in the GC base pair. It is shown that the local protein environment drastically increases the activation and reaction energies for the double proton transfer, modifying the tautomeric equilibrium. We propose a regime in which the proton transfer is dominated by tunnelling, taking place instantaneously and without atomic rearrangement of the local environment. In this paradigm, we can reconcile the metastable nature of the tautomer and show that ensemble averaging methods obscure detail in the reaction profile. Our results highlight the importance of explicit environmental models and suggest that asparagine N624 serves a secondary function of reducing spontaneous mutations in PcrA Helicase.
Collapse
Affiliation(s)
- Max Winokan
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, GU2 7XH, UK
| | - Louie Slocombe
- School of Chemistry and Chemical Engineering, University of Surrey, Guildford, GU2 7XH, UK
| | - Jim Al-Khalili
- School of Mathematics and Physics, University of Surrey, Guildford, GU2 7XH, UK
| | - Marco Sacchi
- School of Chemistry and Chemical Engineering, University of Surrey, Guildford, GU2 7XH, UK.
| |
Collapse
|
6
|
Pietruszka M, Lipowczan M. Phase coherent quasi-particle formation in biological systems. Biosystems 2023; 233:105020. [PMID: 37716403 DOI: 10.1016/j.biosystems.2023.105020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/30/2023] [Accepted: 09/03/2023] [Indexed: 09/18/2023]
Abstract
The problem of the origin of canonical and aberrant DNA mutations and the contribution of protons to genetic stability is an essential topic in molecular biology. Based on the empirical results, we reconsidered canonical and tautomeric mutations under the two-fluid model of quantum physics. We assumed that the pressure exerted by protons (H+) in the DNA environment, through changes in pH, could alter the concentration ratio of canonical and tautomeric base pairs, which were found to be different at and beyond the criticality level, respectively. We anticipate that the deviation of the cellular system from a specific (critical) temperature at which dynamic entropy reaches a minimum and a critical pH occurs could result in tautomerization and point mutations.
Collapse
Affiliation(s)
- Mariusz Pietruszka
- The University of Silesia, Faculty of Natural Sciences, Institute of Biology, Biotechnology, and Environmental Protection, 28 Jagiellońska St., PL-40032, Katowice, Poland.
| | - Marcin Lipowczan
- The University of Silesia, Faculty of Natural Sciences, Institute of Biology, Biotechnology, and Environmental Protection, 28 Jagiellońska St., PL-40032, Katowice, Poland
| |
Collapse
|
7
|
Botti G, Ceotto M, Conte R. Investigating the Spectroscopy of the Gas Phase Guanine-Cytosine Pair: Keto versus Enol Configurations. J Phys Chem Lett 2023; 14:8940-8947. [PMID: 37768143 PMCID: PMC10577776 DOI: 10.1021/acs.jpclett.3c02073] [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] [Received: 07/26/2023] [Accepted: 09/26/2023] [Indexed: 09/29/2023]
Abstract
We report on a vibrational study of the guanine-cytosine dimer tautomers using state-of-the-art quasiclassical trajectory and semiclassical vibrational spectroscopy. The latter includes possible quantum mechanical effects. Through an accurate comparison to the experimental spectra, we are able to shine a light on the hydrogen bond network of one of the main subunits of DNA and put the experimental assignment on a solid footing. Our calculations corroborate the experimental conclusion that the global minimum Watson-and-Crick structure is not detected in the spectra, and there is no evidence of tunnel-effect-based double proton hopping. Our accurate assignment of the spectral features may also serve as a basis for the development of precise force fields to study the guanine-cytosine dimer.
Collapse
Affiliation(s)
- Giacomo Botti
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Michele Ceotto
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Riccardo Conte
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| |
Collapse
|
8
|
Lu Y, Sen K, Yong C, Gunn DSD, Purton JA, Guan J, Desmoutier A, Abdul Nasir J, Zhang X, Zhu L, Hou Q, Jackson-Masters J, Watts S, Hanson R, Thomas HN, Jayawardena O, Logsdail AJ, Woodley SM, Senn HM, Sherwood P, Catlow CRA, Sokol AA, Keal TW. Multiscale QM/MM modelling of catalytic systems with ChemShell. Phys Chem Chem Phys 2023; 25:21816-21835. [PMID: 37097706 DOI: 10.1039/d3cp00648d] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Hybrid quantum mechanical/molecular mechanical (QM/MM) methods are a powerful computational tool for the investigation of all forms of catalysis, as they allow for an accurate description of reactions occurring at catalytic sites in the context of a complicated electrostatic environment. The scriptable computational chemistry environment ChemShell is a leading software package for QM/MM calculations, providing a flexible, high performance framework for modelling both biomolecular and materials catalysis. We present an overview of recent applications of ChemShell to problems in catalysis and review new functionality introduced into the redeveloped Python-based version of ChemShell to support catalytic modelling. These include a fully guided workflow for biomolecular QM/MM modelling, starting from an experimental structure, a periodic QM/MM embedding scheme to support modelling of metallic materials, and a comprehensive set of tutorials for biomolecular and materials modelling.
Collapse
Affiliation(s)
- You Lu
- STFC Scientific Computing, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.
| | - Kakali Sen
- STFC Scientific Computing, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.
| | - Chin Yong
- STFC Scientific Computing, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.
| | - David S D Gunn
- STFC Scientific Computing, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.
| | - John A Purton
- STFC Scientific Computing, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.
| | - Jingcheng Guan
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Alec Desmoutier
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Jamal Abdul Nasir
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Xingfan Zhang
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Lei Zhu
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Qing Hou
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Joe Jackson-Masters
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - Sam Watts
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - Rowan Hanson
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - Harry N Thomas
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - Omal Jayawardena
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - Andrew J Logsdail
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - Scott M Woodley
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Hans M Senn
- School of Chemistry, University of Glasgow, Joseph Black Building, Glasgow G12 8QQ, UK
| | - Paul Sherwood
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
| | - C Richard A Catlow
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - Alexey A Sokol
- Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Thomas W Keal
- STFC Scientific Computing, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.
| |
Collapse
|
9
|
Salgado-Blanco D, Flores-Saldaña DSM, Jaimes-Miranda F, López-Urías F. Electronic and magnetic properties of TATA-DNA sequence driven by chemical functionalization. J Comput Chem 2023; 44:1199-1207. [PMID: 36704941 DOI: 10.1002/jcc.27079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 12/06/2022] [Accepted: 01/08/2023] [Indexed: 01/28/2023]
Abstract
The TATA box is a promoter sequence able to interact directly with the components of the basal transcription initiation machinery. We investigate the changes in the electronic and magnetic properties of a TATA-DNA sequence when functionalized with different chemical groups; using the first-principles density functional theory specifically, the TATA-DNA sequences were functionalized with methyl groups (CH3 , methylation), amino groups (NH2 , amination), imine groups (NH, imination), chloroamine groups (NCl2 , chloramination), H-adatom (hydrogenation), and Cl-adatom (chlorination). The functional groups were anchored at nitrogen atoms from adenine and oxygen atoms from thymine at sites pointed as reactive regions. We demonstrated that chemical functionalization induces significant changes in charge transfer, hydrogen bond distance, and hydrogen bond energy. The hydrogenation and imination increased the hydrogen bond energy. Results also revealed that the chemical functionalization of DNA molecules exhibit a ferromagnetic ground state, reaching magnetization up to 4.665 μB and complex magnetic ordering. We further demonstrated that the functionalization could induce tautomerism (proton migration in the base pair systems). The present study provides a theoretical basis for understanding the functionalization further into DNA molecules and visualizing possible future applications.
Collapse
Affiliation(s)
- Daniel Salgado-Blanco
- Cátedra-Conacyt, Centro Nacional de Supercómputo, IPICyT, San Luis Potosí, Mexico
- División de Materiales Avanzados, IPICyT, San Luis Potosí, Mexico
| | - Diana S M Flores-Saldaña
- Engineering in Nanotechnologies and Energies, San Luis Potosí Autonomous University, San Luis Potosí, Mexico
| | | | | |
Collapse
|
10
|
Peng HC, Castro GL, Karthikeyan V, Jarrett A, Katz MA, Hargrove JA, Hoang D, Hilber S, Meng W, Wang L, Fick RJ, Ahn JM, Kreutz C, Stelling AL. Measuring the Enthalpy of an Individual Hydrogen Bond in a DNA Duplex with Nucleobase Isotope Editing and Variable-Temperature Infrared Spectroscopy. J Phys Chem Lett 2023; 14:4313-4321. [PMID: 37130045 DOI: 10.1021/acs.jpclett.3c00178] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The level of interest in probing the strength of noncovalent interactions in DNA duplexes is high, as these weak forces dictate the range of suprastructures the double helix adopts under different conditions, in turn directly impacting the biological functions and industrial applications of duplexes that require making and breaking them to access the genetic code. However, few experimental tools can measure these weak forces embedded within large biological suprastructures in the native solution environment. Here, we develop experimental methods for detecting the presence of a single noncovalent interaction [a hydrogen bond (H-bond)] within a large DNA duplex in solution and measure its formation enthalpy (ΔHf). We report that introduction of a H-bond into the TC2═O group from the noncanonical nucleobase 2-aminopurine produces an expected decrease ∼10 ± 0.76 cm-1 (from ∼1720 cm-1 in Watson-Crick to ∼1710 cm-1 in 2-aminopurine), which correlates with an enthalpy of ∼0.93 ± 0.066 kcal/mol for this interaction.
Collapse
Affiliation(s)
- Hao-Che Peng
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Gabrielle L Castro
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Varshini Karthikeyan
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Alina Jarrett
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Melanie A Katz
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - James A Hargrove
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - David Hoang
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Stefan Hilber
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck 6020, Austria
| | - Wenting Meng
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Lu Wang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Robert J Fick
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Jung-Mo Ahn
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck 6020, Austria
| | - Allison L Stelling
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| |
Collapse
|
11
|
Warman H, Slocombe L, Sacchi M. How proton transfer impacts hachimoji DNA. RSC Adv 2023; 13:13384-13396. [PMID: 37143915 PMCID: PMC10152326 DOI: 10.1039/d3ra00983a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/23/2023] [Indexed: 05/06/2023] Open
Abstract
Hachimoji DNA is a synthetic nucleic acid extension of DNA, formed by an additional four bases, Z, P, S, and B, that can encode information and sustain Darwinian evolution. In this paper, we aim to look into the properties of hachimoji DNA and investigate the probability of proton transfer between the bases, resulting in base mismatch under replication. First, we present a proton transfer mechanism for hachimoji DNA, analogous to the one presented by Löwdin years prior. Then, we use density functional theory to calculate proton transfer rates, tunnelling factors and the kinetic isotope effect in hachimoji DNA. We determined that the reaction barriers are sufficiently low that proton transfer is likely to occur even at biological temperatures. Furthermore, the rates of proton transfer of hachimoji DNA are much faster than in Watson-Crick DNA due to the barrier for Z-P and S-B being 30% lower than in G-C and A-T. Suggesting that proton transfer occurs more frequently in hachimoji DNA than canonical DNA, potentially leading to a higher mutation rate.
Collapse
Affiliation(s)
- Harry Warman
- School of Physics and Maths, University of Surrey Guildford GU2 7XH UK
| | - Louie Slocombe
- School of Chemistry and Chemical Engineering, University of Surrey Guildford GU2 7XH UK
| | - Marco Sacchi
- School of Chemistry and Chemical Engineering, University of Surrey Guildford GU2 7XH UK
| |
Collapse
|
12
|
King B, Winokan M, Stevenson P, Al-Khalili J, Slocombe L, Sacchi M. Tautomerisation Mechanisms in the Adenine-Thymine Nucleobase Pair during DNA Strand Separation. J Phys Chem B 2023; 127:4220-4228. [PMID: 36939840 DOI: 10.1021/acs.jpcb.2c08631] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
Abstract
The adenine-thymine tautomer (A*-T*) has previously been discounted as a spontaneous mutagenesis mechanism due to the energetic instability of the tautomeric configuration. We study the stability of A*-T* while the nucleobases undergo DNA strand separation. Our calculations indicate an increase in the stability of A*-T* as the DNA strands unzip and the hydrogen bonds between the bases stretch. Molecular Dynamics simulations reveal the time scales and dynamics of DNA strand separation and the statistical ensemble of opening angles present in a biological environment. Our results demonstrate that the unwinding of DNA, an inherently out-of-equilibrium process facilitated by helicase, will change the energy landscape of the adenine-thymine tautomerization reaction. We propose that DNA strand separation allows the stable tautomerization of adenine-thymine, providing a feasible pathway for genetic point mutations via proton transfer between the A-T bases.
Collapse
Affiliation(s)
- Benjamin King
- Department of Physics, University of Surrey, Guildford GU2 7XH, U.K
| | - Max Winokan
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 7XH, U.K
| | - Paul Stevenson
- Department of Physics, University of Surrey, Guildford GU2 7XH, U.K
| | - Jim Al-Khalili
- Department of Physics, University of Surrey, Guildford GU2 7XH, U.K
| | - Louie Slocombe
- School of Chemistry and Chemical Engineering, University of Surrey, Guildford GU2 7XH, U.K
| | - Marco Sacchi
- School of Chemistry and Chemical Engineering, University of Surrey, Guildford GU2 7XH, U.K
| |
Collapse
|
13
|
Fatahiyan L, Taghva Manesh A, Masnabadi N. Tautomerization reactions of thiobarbituric acid: A detailed kinetic study using combined canonical variational transition state theory and QTAIM approach. INT J CHEM KINET 2023. [DOI: 10.1002/kin.21632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Affiliation(s)
- Leila Fatahiyan
- Department of Chemistry, Central Tehran Branch, Islamic Azad University Tehran Iran
| | - Afshin Taghva Manesh
- Department of Chemistry, Central Tehran Branch, Islamic Azad University Tehran Iran
| | - Nasrin Masnabadi
- Department of Chemistry, Roudehen Branch, Islamic Azad University Roudehen Iran
| |
Collapse
|
14
|
Umesaki K, Odai K. Tunneling Effect in Proton Transfer: Transfer Matrix Approach. J Phys Chem A 2023; 127:1046-1052. [PMID: 36689270 DOI: 10.1021/acs.jpca.2c05880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The transfer matrix (TM) method was applied to calculate the transmission probability (TP) for proton transfer reactions. The tunneling factors in the reaction rate constants were also evaluated using the TPs. To test this method, TPs for the Eckart potentials modeled as a guanine-cytosine base pair were calculated by the TM method and compared to TPs by the analytical solution. As a result, the errors in the TPs by the TM method were quite small. The tunneling factors for the guanine-thymine (G-T) and adenine-cytosine (A-C) mispair reactions were then evaluated by the TM method. A shoulder appears on each potential for these reactions [Odai, K.; Umesaki,K. J. Phys. Chem. A. 2021, 125, 8196-8204]. As a result, the shoulder for the G-T mispair reaction contributes significantly to the tunneling, while the shoulder for the A-C mispair reaction contributes little to the tunneling. These results are difficult to obtain with methods such as Wigner's tunneling factor.
Collapse
Affiliation(s)
- Keisho Umesaki
- School of Science and Engineering, Kokushikan University, Setagaya-ku, Tokyo154-8515, Japan
| | - Kei Odai
- School of Science and Engineering, Kokushikan University, Setagaya-ku, Tokyo154-8515, Japan
| |
Collapse
|
15
|
Slocombe L, Winokan M, Al-Khalili J, Sacchi M. Quantum Tunnelling Effects in the Guanine-Thymine Wobble Misincorporation via Tautomerism. J Phys Chem Lett 2023; 14:9-15. [PMID: 36562711 PMCID: PMC9841559 DOI: 10.1021/acs.jpclett.2c03171] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/19/2022] [Indexed: 05/22/2023]
Abstract
The misincorporation of a noncomplementary DNA base in the polymerase active site is a critical source of replication errors that can lead to genetic mutations. In this work, we model the mechanism of wobble mispairing and the subsequent rate of misincorporation errors by coupling first-principles quantum chemistry calculations to an open quantum systems master equation. This methodology allows us to accurately calculate the proton transfer between bases, allowing the misincorporation and formation of mutagenic tautomeric forms of DNA bases. Our calculated rates of genetic error formation are in excellent agreement with experimental observations in DNA. Furthermore, our quantum mechanics/molecular mechanics model predicts the existence of a short-lived "tunnelling-ready" configuration along the wobble reaction pathway in the polymerase active site, dramatically increasing the rate of proton transfer by a hundredfold, demonstrating that quantum tunnelling plays a critical role in determining the transcription error frequency of the polymerase.
Collapse
Affiliation(s)
- Louie Slocombe
- Leverhulme
Quantum Biology Doctoral Training Centre, University of Surrey, GuildfordGU2 7XH, U.K.
- Department
of Chemistry, University of Surrey, GuildfordGU2 7XH, U.K.
| | - Max Winokan
- Leverhulme
Quantum Biology Doctoral Training Centre, University of Surrey, GuildfordGU2 7XH, U.K.
| | - Jim Al-Khalili
- Department
of Physics, University of Surrey, GuildfordGU2 7XH, U.K.
| | - Marco Sacchi
- Department
of Chemistry, University of Surrey, GuildfordGU2 7XH, U.K.
| |
Collapse
|
16
|
Slocombe L, Winokan M, Al-Khalili J, Sacchi M. Proton transfer during DNA strand separation as a source of mutagenic guanine-cytosine tautomers. Commun Chem 2022; 5:144. [PMID: 36697962 PMCID: PMC9814255 DOI: 10.1038/s42004-022-00760-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/14/2022] [Indexed: 11/06/2022] Open
Abstract
Proton transfer between the DNA bases can lead to mutagenic Guanine-Cytosine tautomers. Over the past several decades, a heated debate has emerged over the biological impact of tautomeric forms. Here, we determine that the energy required for generating tautomers radically changes during the separation of double-stranded DNA. Density Functional Theory calculations indicate that the double proton transfer in Guanine-Cytosine follows a sequential, step-like mechanism where the reaction barrier increases quasi-linearly with strand separation. These results point to increased stability of the tautomer when the DNA strands unzip as they enter the helicase, effectively trapping the tautomer population. In addition, molecular dynamics simulations indicate that the relevant strand separation time is two orders of magnitude quicker than previously thought. Our results demonstrate that the unwinding of DNA by the helicase could simultaneously slow the formation but significantly enhance the stability of tautomeric base pairs and provide a feasible pathway for spontaneous DNA mutations.
Collapse
Affiliation(s)
- Louie Slocombe
- grid.5475.30000 0004 0407 4824Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, GU2 7XH UK ,grid.5475.30000 0004 0407 4824Department of Chemistry, University of Surrey, Guildford, GU2 7XH UK
| | - Max Winokan
- grid.5475.30000 0004 0407 4824Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, GU2 7XH UK
| | - Jim Al-Khalili
- grid.5475.30000 0004 0407 4824Department of Physics, University of Surrey, Guildford, GU2 7XH UK
| | - Marco Sacchi
- grid.5475.30000 0004 0407 4824Department of Chemistry, University of Surrey, Guildford, GU2 7XH UK
| |
Collapse
|
17
|
Zhang X, Zhu Z, Liu W, Gao F, Guo J, Song B, Lee LP, Zhang F. The Selective Function of Quantum Biological Electron Transfer between DNA Bases and Metal Ions in DNA Replication. J Phys Chem Lett 2022; 13:7779-7787. [PMID: 35969805 DOI: 10.1021/acs.jpclett.2c01877] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metal ions play vital roles in the electron transfer between biological molecules in humans, animals, and plants. However, the electron transfer between metal ions and nucleic acids and its impact on DNA-ion binding during DNA replication has been ignored. Here, we present a long-range quantum biological electron transfer (QBET) between DNA bases and metal ions and its selective function of DNA-ion binding in DNA replication. We discover biophysical DNA-ion binding and create biological filters that allow selective DNA replication by dual modulators of the valence and concentration of metal ions. QBET-based DNA replication filters provide powerful tools for ultrasensitive polymerase chain reaction (PCR) to selectively amplify target sequences with a discrete concentration window of metal ions; for example, Au3+ exhibits a concentration window that is approximately 3 orders of magnitude lower than that of Na+. DNA-ion filters provide new perspectives into metal ion-mediated QBET in DNA replication and hold great potential in life sciences and medical applications.
Collapse
Affiliation(s)
- Xianjing Zhang
- Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Zhi Zhu
- Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Wenpeng Liu
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Feng Gao
- Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Jun Guo
- Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Bo Song
- Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Luke P Lee
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Bioengineering, Department of Electrical Engineering and Computer Science, University of California, Berkeley, California 94720, United States
- Institute of Quantum Biophysics, Department of Biophysics, Sungkyunkwan University, Suwon 16419, Korea
| | - Feng Zhang
- Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Oral Disease, Stomatology Hospital, School of Biomedical Engineering, Guangzhou Medical University, Guangzhou 511436, China
| |
Collapse
|
18
|
Moe MM, Benny J, Liu J. Collision-induced dissociation of homodimeric and heterodimeric radical cations of 9-methylguanine and 9-methyl-8-oxoguanine: correlation between intra-base pair proton transfer originating from the N1-H at a Watson-Crick edge and non-statistical dissociation. Phys Chem Chem Phys 2022; 24:9263-9276. [PMID: 35403654 DOI: 10.1039/d2cp00312k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It has been shown previously in protonated, deprotonated and ionized guanine-cytosine base pairs that intra-base pair proton transfer from the N1-H at the Watson-Crick edge of guanine to the complementary nucleobase prompts non-statistical dissociation of the base-pair system, and the dissociation of a proton-transferred base-pair structure is kinetically more favored than that of the starting, conventional base-pair structure. However, the fundamental chemistry underlying this anomalous and intriguing kinetics has not been completely revealed, which warrants the examination of more base-pair systems in different structural contexts in order to derive a generalized base-pair structure-kinetics correlation. The purpose of the present work is to expand the investigation to the non-canonical homodimeric and heterodimeric radical cations of 9-methylguanine (9MG) and 9-methyl-8-oxoguanine (9MOG), i.e., [9MG·9MG]˙+, [9MOG·9MG]˙+ and [9MOG·9MOG]˙+. Experimentally, collision-induced dissociation tandem mass spectrometry coupled with an electrospray ionization (ESI) source was used for the formation of base-pair radical cations, followed by detection of dissociation product ions and cross sections in the collisions with Xe gas under single ion-molecule collision conditions and as a function of the center-of-mass collision energy. Computationally, density functional theory and coupled cluster theory were used to calculate and identify probable base-pair structures and intra-base pair proton transfer and hydrogen transfer reactions, followed by kinetics modeling to explore the properties of dissociation transition states and kinetic factors. The significance of this work is twofold: it provides insight into base-pair opening kinetics in three biologically-important, non-canonical systems upon oxidative and ionization damage; and it links non-statistical dissociation to intra-base pair proton-transfer originating from the N1-H at the Watson-Crick edge of 8-oxoguanine, enhancing understanding towards the base-pair fragmentation assisted by proton transfer.
Collapse
Affiliation(s)
- May Myat Moe
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY 11367, USA. .,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY 10016, USA
| | - Jonathan Benny
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY 11367, USA. .,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY 10016, USA
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY 11367, USA. .,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY 10016, USA
| |
Collapse
|
19
|
Brovarets’ OO, Muradova A, Hovorun DM. Novel horizons of the conformationally-tautomeric transformations of the G·T base pairs: quantum-mechanical investigation. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2026510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ol’ha O. Brovarets’
- Department of Molecular and Quantum Biophysics, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Alona Muradova
- Department of Molecular Biotechnology and Bioinformatics, Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
| | - Dmytro M. Hovorun
- Department of Molecular and Quantum Biophysics, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
- Department of Molecular Biotechnology and Bioinformatics, Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
| |
Collapse
|
20
|
Hajali N, Taghva Manesh A, Seif A. A detailed kinetic study on the tautomerization reactions of barbituric acid: A combined DFT-QTAIM analysis. MAIN GROUP CHEMISTRY 2022. [DOI: 10.3233/mgc-210169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A detailed kinetic study on the tautomerization reactions of barbituric acid (BA) at elevated temperatures from 270 K up to 1000 K was performed in this work. The B3LYP/6-311 + G(3df,2p) density functional theory (DFT) calculations were performed to evaluate the rate constants of transition states (TS) conversions of the tautomerization reactions. The connections from a given TS to the corresponding local minima of the reactant and product sides were confirmed by means of employing the intrinsic reaction coordinate (IRC) method. Moreover, the quantum theory of atoms in molecules (QTAIM) approach was employed to analyze the molecular mechanisms of reactions. The effects of vibrational normal mode frequencies of the reactant and TS were investigated on the curvature of the corresponding Arrhenius plot in the presence and absence of the tunneling effect. For each tautomerization reaction, the investigated reaction was partitioned into three different stages and four zones. The obtained results were plotted along with the corresponding reaction coordinates for each reaction considering and comparing different factors in agreement with already affirmed concepts. As a consequence, details of performed kinetic study on the tautomerization reactions of BA were successfully provided in this work.
Collapse
Affiliation(s)
- Narjes Hajali
- Department of Chemistry, Faculty of Science, Central Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Afshin Taghva Manesh
- Department of Chemistry, Faculty of Science, Central Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Ahmad Seif
- Department of Chemistry, Faculty of Science, Central Tehran Branch, Islamic Azad University, Tehran, Iran
| |
Collapse
|
21
|
Behboodyzad F, Mohseniabbasabadi T, Ghanemnia N, Balali E. Structural analysis of dexrazoxane: Exploring tautomeric conformations. MAIN GROUP CHEMISTRY 2021. [DOI: 10.3233/mgc-210158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Structural analysis of dexrazoxane, as a cardioprotective agent, was done in this work by exploring formations of tautomeric conformations and investigating the corresponding effects. Density functional theory (DFT) calculations were performed to optimize the structures to evaluate their molecular and atomic descriptors. In addition to the original structure of dexrazoxane, eight tautomers were obtained with lower stability than the original compound. Movements of two hydrogen atoms in between nitrogen and oxygen atoms of heterocyclic ring put such significant effects. Moreover, electronic molecular orbital features showed effects of such tautomerism processes on distribution patterns and surfaces, in which evaluating the quadrupole coupling constants helped to show the role of atomic sites for resulting the features. As a consequence, the results indicated that the tautomeric formations could significantly change the features of dexrazoxane reminding the importance of carful medication of this drug for patients.
Collapse
Affiliation(s)
- Farnoosh Behboodyzad
- Department of Organic Chemistry, Faculty of Pharmaceutical Chemistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Tahereh Mohseniabbasabadi
- Department of Organic Chemistry, Faculty of Pharmaceutical Chemistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Nahal Ghanemnia
- Department of Molecular Sciences and Nanosystems, Faculty of Science and Technology of Bio and Nanomaterials, University of Ca’ Foscari, Venice, Italy
| | - Ebrahim Balali
- Department of Organic Chemistry, Faculty of Pharmaceutical Chemistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| |
Collapse
|
22
|
Rad AJ, Abbasi M, Zohrevand B. Iron Chelation by thiocytosine: Investigating electronic and structural features for describing tautomerism and metal chelation processes. MAIN GROUP CHEMISTRY 2021. [DOI: 10.3233/mgc-210110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This work was performed regarding the importance of iron (Fe) chelation for biological systems. This goal was investigated by assistance of a model of thiocytosine (TC) for participating in Fe-chelation processes. First, formations of tautomeric conformations were investigated to explore existence of possible structures of TC. Next, Fe-chelation processes were examined for all four obtained tautomers of TC. The results indicated that thiol tautomers could be seen at higher stability than thio tautomers, in which one of such thiol tautomers yielded the strongest Fe-chelation process to build FeTC3 model. As a consequence, parallel to the results of original TC tautomers, Fe-chelated models were found to be achievable for meaningful chelation processes or sensing the existence of Fe in media. Examining molecular orbital features could help for sensing purposes. The results of this work were obtained by performing density functional theory (DFT) calculations proposing TC compounds suitable for Fe-chelation purposes.
Collapse
Affiliation(s)
- Azadeh Jafari Rad
- Department of Chemistry, Omidiyeh Branch, Islamic Azad University, Omidiyeh, Iran
| | - Maryam Abbasi
- Department of Chemistry, Payame Noor University, Tehran, Iran
| | - Bahareh Zohrevand
- Department of Chemistry, Central Tehran Branch, Islamic Azad University, Tehran, Iran
| |
Collapse
|
23
|
Slocombe L, Al-Khalili JS, Sacchi M. Quantum and classical effects in DNA point mutations: Watson-Crick tautomerism in AT and GC base pairs. Phys Chem Chem Phys 2021; 23:4141-4150. [PMID: 33533770 DOI: 10.1039/d0cp05781a] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Proton transfer along the hydrogen bonds of DNA can lead to the creation of short-lived, but biologically relevant point mutations that can further lead to gene mutation and, potentially, cancer. In this work, the energy landscape of the canonical A-T and G-C base pairs (standard, amino-keto) to tautomeric A*-T* and G*-C* (non-standard, imino-enol) Watson-Crick DNA base pairs is modelled with density functional theory and machine-learning nudge-elastic band methods. We calculate the energy barriers and tunnelling rates of hydrogen transfer between and within each base monomer (A, T, G and C). We show that the role of tunnelling in A-T tautomerisation is statistically unlikely due to the presence of a small reverse reaction barrier. On the contrary, the thermal populations of the G*-C* point mutation could be non-trivial and propagate through the replisome. For the direct intramolecular transfer, the reaction is hindered by a substantial energy barrier. However, our calculations indicate that tautomeric bases in their monomeric form have remarkably long lifetimes.
Collapse
Affiliation(s)
- L Slocombe
- Leverhulme Quantum Biology Doctoral Training Centre, UK.
| | - J S Al-Khalili
- Department of Physics, University of Surrey, Guildford, GU2 7XH, UK
| | - M Sacchi
- Department of Chemistry, University of Surrey, Guildford, GU2 7XH, UK.
| |
Collapse
|
24
|
Gheorghiu A, Coveney PV, Arabi AA. The influence of external electric fields on proton transfer tautomerism in the guanine-cytosine base pair. Phys Chem Chem Phys 2021; 23:6252-6265. [PMID: 33735350 PMCID: PMC8330266 DOI: 10.1039/d0cp06218a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/23/2021] [Indexed: 12/28/2022]
Abstract
The Watson-Crick base pair proton transfer tautomers would be widely considered as a source of spontaneous mutations in DNA replication if not for their short lifetimes and thermodynamic instability. This work investigates the effects external electric fields have on the stability of the guanine-cytosine proton transfer tautomers within a realistic strand of aqueous DNA using a combination of ensemble-based classical molecular dynamics (MD) coupled to quantum mechanics/molecular mechanics (QM/MM). Performing an ensemble of calculations accounts for the stochastic aspects of the simulations while allowing for easier identification of systematic errors. The methodology applied in this work has previously been shown to estimate base pair proton transfer rate coefficients that are in good agreement with recent experimental data. A range of electric fields in the order of 104 to 109 V m-1 is investigated based on their real-life medicinal applications which include gene therapy and cancer treatments. The MD trajectories confirm that electric fields up to 1.00 × 109 V m-1 have a negligible influence on the structure of the base pairs within DNA. The QM/MM results show that the application of large external electric fields (1.00 × 109 V m-1) parallel to the hydrogen bonds increases the thermodynamic population of the tautomers by up to one order of magnitude; moreover, the lifetimes of the tautomers remain insignificant when compared to the timescale of DNA replication.
Collapse
Affiliation(s)
- Alexander Gheorghiu
- Centre for Computational Science, University College London, 20 Gordon St, London, WC1H 0AJ, UK.
| | - Peter V Coveney
- Centre for Computational Science, University College London, 20 Gordon St, London, WC1H 0AJ, UK. and Informatics Institute, University of Amsterdam, P.O. Box 94323 1090 GH, Amsterdam, The Netherlands
| | - Alya A Arabi
- Centre for Computational Science, University College London, 20 Gordon St, London, WC1H 0AJ, UK. and College of Medicine and Health Sciences, Biochemistry Department, United Arab Emirates University, AlAin, P. O. Box: 17666, United Arab Emirates.
| |
Collapse
|
25
|
Affiliation(s)
- Peter V. Coveney
- Centre for Computational Science, University College London, London, UK
- Informatics Institute, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|