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Beierlein F, Volkenandt S, Imhof P. Oxidation Enhances Binding of Extrahelical 5-Methyl-Cytosines by Thymine DNA Glycosylase. J Phys Chem B 2022; 126:1188-1201. [PMID: 35109648 DOI: 10.1021/acs.jpcb.1c09896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The DNA repair protein thymine DNA glycosylase (TDG) removes mispaired or damaged bases, such as oxidized methyl-cytosine, from DNA by cleavage of the glycosidic bond between the sugar and the target base flipped into the enzyme's active site. The enzyme is active against formyl-cytosine and carboxyl-cytosine, whereas the lower oxidized hydroxymethyl-cytosine and methyl-cytosine itself are not processed by the enzyme. Molecular dynamics simulations with thermodynamic integration of TDG complexed to DNA carrying one of four different (oxidized) methyl-cytosine bases in extrahelcial conformation, methyl-cytosine (mC), hydroxymethyl-cytosine (hmC), formyl-cytosine (fC), or carboxyl-cytosine (caC), show a more favorable binding affinity of the higher oxidized forms, fC and caC, than the nonsubstrate bases hmC and mC. Despite rather comparable, reaction-competent conformations of the flipped bases in the active site of the enzyme, more and stronger interactions with active site residues account for the preferred binding of the higher oxidized bases. Binding of the negatively charged caC and the neutral fC are strengthened by interactions with positively charged His151. Our calculated proton affinities find this protonation state of His151 the preferred one in the presence of caC and conceivable in the presence of fC as well as increasing the binding affinity toward the two bases. Discrimination of the substrate bases is further achieved by the backbone of Tyr152 that forms a strong hydrogen bond to the carboxyl and formyl oxygen atoms of caC and fC, respectively, a contact that is completely lacking in mC and much weaker in hmC. Overall, our computational results indicate that the enzyme discriminates the different oxidation forms of methyl-cytosine already at the formation of the extrahelical complexes.
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Affiliation(s)
- Frank Beierlein
- Department for Chemistry and Pharmacy Computer Chemistry Centre, Friedrich-Alexander University (FAU) Erlangen Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany.,Erlangen National High Performance Computing Center (NHR@FAU), Friedrich-Alexander University (FAU) Erlangen Nürnberg, Martensstraße 1, 91058 Erlangen, Germany
| | - Senta Volkenandt
- Department for Chemistry and Pharmacy Computer Chemistry Centre, Friedrich-Alexander University (FAU) Erlangen Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany.,Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Petra Imhof
- Department for Chemistry and Pharmacy Computer Chemistry Centre, Friedrich-Alexander University (FAU) Erlangen Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany.,Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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Interaction of Thymine DNA Glycosylase with Oxidised 5-Methyl-cytosines in Their Amino- and Imino-Forms. Molecules 2021; 26:molecules26195728. [PMID: 34641273 PMCID: PMC8510025 DOI: 10.3390/molecules26195728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/03/2021] [Accepted: 09/13/2021] [Indexed: 11/16/2022] Open
Abstract
Thymine DNA Glycosylase (TDG) is an enzyme of the base excision repair mechanism and removes damaged or mispaired bases from DNA via hydrolysis of the glycosidic bond. Specificity is of high importance for such a glycosylase, so as to avoid the damage of intact DNA. Among the substrates reported for TDG are mispaired uracil and thymine but also formyl-cytosine and carboxyl-cytosine. Methyl-cytosine and hydroxylmethyl-cytosine are, in contrast, not processed by the TDG enzyme. We have in this work employed molecular dynamics simulations to explore the conformational dynamics of DNA carrying a formyl-cytosine or carboxyl-cytosine and compared those to DNA with the non-cognate bases methyl-cytosine and hydroxylmethyl-cytosine, as amino and imino tautomers. Whereas for the mispairs a wobble conformation is likely decisive for recognition, all amino tautomers of formyl-cytosine and carboxyl-cytosine exhibit the same Watson–Crick conformation, but all imino tautomers indeed form wobble pairs. The conformational dynamics of the amino tautomers in free DNA do not exhibit differences that could be exploited for recognition, and also complexation to the TDG enzyme does not induce any alteration that would indicate preferable binding to one or the other oxidised methyl-cytosine. The imino tautomers, in contrast, undergo a shift in the equilibrium between a closed and a more open, partially flipped state, towards the more open form upon complexation to the TDG enzyme. This stabilisation of the more open conformation is most pronounced for the non-cognate bases methyl-cytosine and hydroxyl-cytosine and is thus not a likely mode for recognition. Moreover, calculated binding affinities for the different forms indicate the imino forms to be less likely in the complexed DNA. These findings, together with the low probability of imino tautomers in free DNA and the indifference of the complexed amino tautomers, suggest that discrimination of the oxidised methyl-cytosines does not take place in the initial complex formation.
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Ahn SY, Liu J, Vellampatti S, Wu Y, Um SH. DNA Transformations for Diagnosis and Therapy. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2008279. [PMID: 33613148 PMCID: PMC7883235 DOI: 10.1002/adfm.202008279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/22/2020] [Indexed: 05/03/2023]
Abstract
Due to its unique physical and chemical characteristics, DNA, which is known only as genetic information, has been identified and utilized as a new material at an astonishing rate. The role of DNA has increased dramatically with the advent of various DNA derivatives such as DNA-RNA, DNA-metal hybrids, and PNA, which can be organized into 2D or 3D structures by exploiting their complementary recognition. Due to its intrinsic biocompatibility, self-assembly, tunable immunogenicity, structural programmability, long stability, and electron-rich nature, DNA has generated major interest in electronic and catalytic applications. Based on its advantages, DNA and its derivatives are utilized in several fields where the traditional methodologies are ineffective. Here, the present challenges and opportunities of DNA transformations are demonstrated, especially in biomedical applications that include diagnosis and therapy. Natural DNAs previously utilized and transformed into patterns are not found in nature due to lack of multiplexing, resulting in low sensitivity and high error frequency in multi-targeted therapeutics. More recently, new platforms have advanced the diagnostic ability and therapeutic efficacy of DNA in biomedicine. There is confidence that DNA will play a strong role in next-generation clinical technology and can be used in multifaceted applications.
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Affiliation(s)
- So Yeon Ahn
- School of Chemical EngineeringSungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi‐do16419Korea
| | - Jin Liu
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia MedicaSchool of Chemistry and Chemical Engineering Huazhong University of Science and Technology1037 Luoyu LoadWuhan430074China
| | - Srivithya Vellampatti
- Institute of Convergent Chemical Engineering and TechnologySungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi‐do16419Korea
- Present address:
Progeneer, Inc.#1002, 12, Digital‐ro 31‐gil, Guro‐guSeoul08380Korea
| | - Yuzhou Wu
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia MedicaSchool of Chemistry and Chemical Engineering Huazhong University of Science and Technology1037 Luoyu LoadWuhan430074China
| | - Soong Ho Um
- School of Chemical EngineeringSKKU Advanced Institute of Nanotechnology (SAINT)Biomedical Institute for Convergence at SKKU (BICS) and Institute of Quantum Biophysics (IQB)Sungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi‐do16419Korea
- Progeneer Inc.#1002, 12, Digital‐ro 31‐gil, Guro‐guSeoul08380Korea
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Hardwick JS, Haugland MM, El-Sagheer AH, Ptchelkine D, Beierlein FR, Lane AN, Brown T, Lovett JE, Anderson EA. 2'-Alkynyl spin-labelling is a minimally perturbing tool for DNA structural analysis. Nucleic Acids Res 2020; 48:2830-2840. [PMID: 32052020 PMCID: PMC7102949 DOI: 10.1093/nar/gkaa086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 01/28/2020] [Accepted: 02/10/2020] [Indexed: 02/06/2023] Open
Abstract
The determination of distances between specific points in nucleic acids is essential to understanding their behaviour at the molecular level. The ability to measure distances of 2-10 nm is particularly important: deformations arising from protein binding commonly fall within this range, but the reliable measurement of such distances for a conformational ensemble remains a significant challenge. Using several techniques, we show that electron paramagnetic resonance (EPR) spectroscopy of oligonucleotides spin-labelled with triazole-appended nitroxides at the 2' position offers a robust and minimally perturbing tool for obtaining such measurements. For two nitroxides, we present results from EPR spectroscopy, X-ray crystal structures of B-form spin-labelled DNA duplexes, molecular dynamics simulations and nuclear magnetic resonance spectroscopy. These four methods are mutually supportive, and pinpoint the locations of the spin labels on the duplexes. In doing so, this work establishes 2'-alkynyl nitroxide spin-labelling as a minimally perturbing method for probing DNA conformation.
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Affiliation(s)
- Jack S Hardwick
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Marius M Haugland
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Afaf H El-Sagheer
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
- Chemistry Branch, Department of Science and Mathematics, Faculty of Petroleum and Mining Engineering, Suez University, Suez 43721, Egypt
| | - Denis Ptchelkine
- Weatherall Institute of Molecular Medicine, Department of Oncology, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford OX3 9DS, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, OX11 0FA, UK
| | - Frank R Beierlein
- Computer-Chemistry-Center and Interdisciplinary Center for Molecular Materials, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052 Erlangen, Germany
| | - Andrew N Lane
- Center for Environmental and Systems Biochemistry and Department of Toxicology & Cancer Biology, The University of Kentucky, 789 S. Limestone St., Lexington, KY 40536, USA
| | - Tom Brown
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Janet E Lovett
- SUPA School of Physics and Astronomy and BSRC, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
| | - Edward A Anderson
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
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Zozulia O, Bachmann T, Deussner-Helfmann NS, Beierlein F, Heilemann M, Mokhir A. Red light-triggered nucleic acid-templated reaction based on cyclic oligonucleotide substrates. Chem Commun (Camb) 2019; 55:10713-10716. [PMID: 31429427 DOI: 10.1039/c9cc03587g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A red light-triggered reaction based on cyclic oligonucleotide substrates that is accelerated over 30-fold by specific nucleic acid templates and generates a bright fluorescent probe was developed. We confirmed that this reaction is compatible with fluorescence correlation spectroscopy (FCS) thereby allowing detection of nucleic acids down to 1 nM.
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Affiliation(s)
- Oleksii Zozulia
- Department of Chemistry and Pharmacy, Organic Chemistry II, Friedrich-Alexander-University of Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany.
| | - Tobias Bachmann
- Department of Chemistry and Pharmacy, Organic Chemistry II, Friedrich-Alexander-University of Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany.
| | - Nina S Deussner-Helfmann
- Institute of Physical and Theoretical Chemistry, Johann Wolfgang Goethe-University, 60438 Frankfurt, Germany
| | - Frank Beierlein
- Computer-Chemistry-Center and Interdisciplinary Center for Molecular Materials, Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91052 Erlangen, Germany
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Johann Wolfgang Goethe-University, 60438 Frankfurt, Germany
| | - Andriy Mokhir
- Department of Chemistry and Pharmacy, Organic Chemistry II, Friedrich-Alexander-University of Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany.
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