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Sacre L, Pontarelli A, Bahsoun Y, Wilds CJ. Influence of C5‐Substituents on Repair of
O
4
‐Methyl Adducts of Pyrimidines by
O
6
‐Alkylguanine DNA Alkyltransferases. ChemistrySelect 2020. [DOI: 10.1002/slct.202003893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lauralicia Sacre
- Department of Chemistry and Biochemistry Concordia University 7141 Sherbrooke Street West Montréal Québec H4B 1R6 Canada
| | - Alexander Pontarelli
- Department of Chemistry and Biochemistry Concordia University 7141 Sherbrooke Street West Montréal Québec H4B 1R6 Canada
| | - Yehya Bahsoun
- Department of Chemistry and Biochemistry Concordia University 7141 Sherbrooke Street West Montréal Québec H4B 1R6 Canada
| | - Christopher J. Wilds
- Department of Chemistry and Biochemistry Concordia University 7141 Sherbrooke Street West Montréal Québec H4B 1R6 Canada
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Abdu K, Aiertza MK, Wilkinson OJ, Senthong P, Craggs TD, Povey AC, Margison GP, Williams DM. Synthesis of oligodeoxyribonucleotides containing a tricyclic thio analogue of O6-methylguanine and their recognition by MGMT and Atl1. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2020; 39:1108-1121. [PMID: 32449465 DOI: 10.1080/15257770.2020.1764971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Promutagenic O6-alkylguanine adducts in DNA are repaired in humans by O6-methylguanine-DNA-methyltransferase (MGMT) in an irreversible reaction. Here we describe the synthesis of a phosphoramidite that allows the preparation of oligodeoxyribonucleotides (ODNs) containing a novel tricyclic thio analogue of O6-methylguanine in which the third ring bridges the 6-thio group and C7 of a 7-deazapurine. These ODNs are very poor substrates for MGMT and poorly recognised by the alkyltransferase-like protein, Atl1. Examination of the active sites of both MGMT and Atl1 suggest large steric clashes hindering binding of the analogue. Such analogues, if mutagenic, are likely to be highly toxic.
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Affiliation(s)
- Kabir Abdu
- Department of Pure and Industrial Chemistry, Faculty of Physical Sciences, Bayero University, Kano, Nigeria
| | - Miren K Aiertza
- Centre for Chemical Biology, Department of Chemistry, Sheffield Institute for Nucleic Acids, University of Sheffield, Sheffield, UK
| | - Oliver J Wilkinson
- Centre for Chemical Biology, Department of Chemistry, Sheffield Institute for Nucleic Acids, University of Sheffield, Sheffield, UK
| | | | - Timothy D Craggs
- Centre for Chemical Biology, Department of Chemistry, Sheffield Institute for Nucleic Acids, University of Sheffield, Sheffield, UK
| | - Andrew C Povey
- Centre of Epidemiology, Faculty of Biology, Medicine and Health
| | | | - David M Williams
- Centre for Chemical Biology, Department of Chemistry, Sheffield Institute for Nucleic Acids, University of Sheffield, Sheffield, UK
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Copp W, O'Flaherty DK, Wilds CJ. Covalent capture of OGT's active site using engineered human-E. coli chimera and intrastrand DNA cross-links. Org Biomol Chem 2018; 16:9053-9058. [PMID: 30430154 DOI: 10.1039/c8ob02453g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
O 6-Alkylguanine DNA alkyltransferases (AGTs) are proteins found in most organisms whose role is to remove alkylation damage from the O6- and O4-positions of 2'-deoxyguanosine (dG) and thymidine (dT), respectively. Variations in active site residues between AGTs from different organisms leads to differences in repair proficiency: The human variant (hAGT) has a proclivity for removal of alkyl groups at the O6-position of guanine and the E. coli OGT protein has activity towards the O4-position of thymine. A chimeric protein (hOGT) that our laboratory has engineered with twenty of the active site residues mutated in hAGT to those found in OGT, exhibited activity towards a broader range of substrates relative to native OGT. Among the substrates that the hOGT protein was found to act upon was interstrand cross-linked DNA connected by an alkylene linkage at the O6-position of dG to the complementary strand. In the present study the activity of hOGT towards DNA containing alkylene intrastrand cross-links (IaCL) at the O6- and O4-positions respectively of dG and dT, which lack a phosphodiester linkage between the connected residues, was evaluated. The hOGT protein exhibited proficiency at removal of an alkylene linkage at the O6-atom of dG but the O4-position of dT was refractory to protein activity. The activity of the chimeric hOGT protein towards these IaCLs to prepare well defined DNA-protein cross-linked conjugates will enable mechanistic and high resolution structural studies to address the differences observed in the repair adeptness of O4-alkylated dT by the OGT protein relative to other AGT variants.
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Affiliation(s)
- William Copp
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec H4B1R6, Canada.
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Sacre L, O'Flaherty DK, Archambault P, Copp W, Peslherbe GH, Muchall HM, Wilds CJ. O 4 -Alkylated-2-Deoxyuridine Repair by O 6 -Alkylguanine DNA Alkyltransferase is Augmented by a C5-Fluorine Modification. Chembiochem 2018; 19:575-582. [PMID: 29243336 DOI: 10.1002/cbic.201700660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Indexed: 11/10/2022]
Abstract
Oligonucleotides containing various adducts, including ethyl, benzyl, 4-hydroxybutyl and 7-hydroxyheptyl groups, at the O4 atom of 5-fluoro-O4 -alkyl-2'-deoxyuridine were prepared by solid-phase synthesis. UV thermal denaturation studies demonstrated that these modifications destabilised the duplex by approximately 10 °C, relative to the control containing 5-fluoro-2'-deoxyuridine. Circular dichroism spectroscopy revealed that these modified duplexes all adopted a B-form DNA structure. O6 -Alkylguanine DNA alkyltransferase (AGT) from humans (hAGT) was most efficient at repair of the 5-fluoro-O4 -benzyl-2'-deoxyuridine adduct, whereas the thymidine analogue was refractory to repair. The Escherichia coli AGT variant (OGT) was also efficient at removing O4 -ethyl and benzyl adducts of 5-fluoro-2-deoxyuridine. Computational assessment of N1-methyl analogues of the O4 -alkylated nucleobases revealed that the C5-fluorine modification had an influence on reducing the electron density of the O4 -Cα bond, relative to thymine (C5-methyl) and uracil (C5-hydrogen). These results reveal the positive influence of the C5-fluorine atom on the repair of larger O4 -alkyl adducts to expand knowledge of the range of substrates able to be repaired by AGT.
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Affiliation(s)
- Lauralicia Sacre
- Department of Chemistry and Biochemistry and, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke St. West, Montréal, Québec, H4B 1R6, Canada
| | - Derek K O'Flaherty
- Department of Chemistry and Biochemistry and, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke St. West, Montréal, Québec, H4B 1R6, Canada.,Present address: Howard Hughes Medical Institute, Department of Molecular Biology and, Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA, 02114, USA
| | - Philippe Archambault
- Department of Chemistry and Biochemistry and, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke St. West, Montréal, Québec, H4B 1R6, Canada
| | - William Copp
- Department of Chemistry and Biochemistry and, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke St. West, Montréal, Québec, H4B 1R6, Canada
| | - Gilles H Peslherbe
- Department of Chemistry and Biochemistry and, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke St. West, Montréal, Québec, H4B 1R6, Canada
| | - Heidi M Muchall
- Department of Chemistry and Biochemistry and, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke St. West, Montréal, Québec, H4B 1R6, Canada
| | - Christopher J Wilds
- Department of Chemistry and Biochemistry and, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke St. West, Montréal, Québec, H4B 1R6, Canada
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O'Flaherty DK, Wilds CJ. Site-specific covalent capture of human O 6-alkylguanine-DNA-alkyltransferase using single-stranded intrastrand cross-linked DNA. Org Biomol Chem 2018; 15:189-196. [PMID: 27886318 DOI: 10.1039/c6ob02246d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A methodology is reported to conjugate human O6-alkylguanine-DNA-alkyltransferase (hAGT) to the 3'-end of DNA in excellent yields with short reaction times by using intrastrand cross-linked (IaCL) DNA probes. This strategy exploited the substrate specificity of hAGT to generate the desired DNA-protein covalent complex. IaCL DNA linking two thymidine residues, or linking a thymidine residue to a 2'-deoxyguanosine residue (either in a 5'→3' or 3'→5' fashion), lacking a phosphodiester linkage at the cross-linked site, were prepared using a phosphoramidite strategy followed by solid-phase synthesis. All duplexes containing the model IaCL displayed a reduction in thermal stability relative to unmodified control duplexes. The O4-thymidine-alkylene-O4-thymidine and the (5'→3') O6-2'-deoxyguanosine-alkylene-O4-thymidine IaCL DNA adducts were not repaired by any of the AGTs evaluated (human AGT and Escherichia coli homologues, OGT and Ada-C). The (5'→3') O4-thymidine-alkylene-O6-2'-deoxyguanosine IaCL DNA containing a butylene or heptylene tethers were efficiently repaired by the human variant, whereas Ada-C was capable of modestly repairing the heptylene IaCL adduct. The IaCL strategy has expanded the toolbox for hAGT conjugation to DNA strands, without requiring the presence of a complementary DNA sequence. Finally, hAGT was functionalized with a fluorescently-labelled DNA sequence to demonstrate the applicability of this conjugation method.
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Affiliation(s)
- D K O'Flaherty
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec H4B1R6, Canada.
| | - C J Wilds
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec H4B1R6, Canada.
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O'Flaherty DK, Wilds CJ. AGT Activity Towards Intrastrand Crosslinked DNA is Modulated by the Alkylene Linker. Chembiochem 2017; 18:2351-2357. [PMID: 28980757 DOI: 10.1002/cbic.201700450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Indexed: 11/12/2022]
Abstract
DNA oligomers containing dimethylene and trimethylene intrastrand crosslinks (IaCLs) between the O4 and O6 atoms of neighboring thymidine (T) and 2'-deoxyguanosine (dG) residues were prepared by solid-phase synthesis. UV thermal denaturation (Tm ) experiments revealed that these IaCLs had a destabilizing effect on the DNA duplex relative to the control. Circular dichroism spectroscopy suggested these IaCLs induced minimal structural distortions. Susceptibility to dealkylation by reaction with various O6 -alkylguanine DNA alkyltransferases (AGTs) from human and Escherichia coli was evaluated. It was revealed that only human AGT displayed activity towards the IaCL DNA, with reduced efficiency as the IaCL shortened (from four to two methylene linkages). Changing the site of attachment of the ethylene linkage at the 5'-end of the IaCL to the N3 atom of T had minimal influence on duplex stability and structure, and was refractory to AGT activity.
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Affiliation(s)
- Derek K O'Flaherty
- Department of Chemistry and Biochemistry, Concordia University Montreal, 7141 Sherbrooke Street W., Montreal, Quebec, H4B 1R6, Canada.,Present address: Howard Hughes Medical Institute, Department of Molecular Biology and, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Christopher J Wilds
- Department of Chemistry and Biochemistry, Concordia University Montreal, 7141 Sherbrooke Street W., Montreal, Quebec, H4B 1R6, Canada
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Altering Residue 134 Confers an Increased Substrate Range of Alkylated Nucleosides to the E. coli OGT Protein. Molecules 2017; 22:molecules22111948. [PMID: 29137116 PMCID: PMC6150290 DOI: 10.3390/molecules22111948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/01/2017] [Accepted: 11/08/2017] [Indexed: 01/20/2023] Open
Abstract
O6-Alkylguanine-DNA alkyltransferases (AGTs) are proteins responsible for the removal of mutagenic alkyl adducts at the O6-atom of guanine and O4-atom of thymine. In the current study we set out to understand the role of the Ser134 residue in the Escherichia coli AGT variant OGT on substrate discrimination. The S134P mutation in OGT increased the ability of the protein to repair both O6-adducts of guanine and O4-adducts of thymine. However, the S134P variant was unable, like wild-type OGT, to repair an interstrand cross-link (ICL) bridging two O6-atoms of guanine in a DNA duplex. When compared to the human AGT protein (hAGT), the S134P OGT variant displayed reduced activity towards O6-alkylation but a much broader substrate range for O4-alkylation damage reversal. The role of residue 134 in OGT is similar to its function in the human homolog, where Pro140 is crucial in conferring on hAGT the capability to repair large adducts at the O6-position of guanine. Finally, a method to generate a covalent conjugate between hAGT and a model nucleoside using a single-stranded oligonucleotide substrate is demonstrated.
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Sacre L, Wilds CJ. Fluorine at the C5 Position of 2′-Deoxyuridine Enhances Repair of a O
4
-Methyl Adduct by O
6
-Alkylguanine DNA Alkyltransferases. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700466] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Lauralicia Sacre
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics; Concordia University; 7141 Sherbrooke St. West H4B 1R6 Montréal Québec Canada
| | - Christopher J. Wilds
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics; Concordia University; 7141 Sherbrooke St. West H4B 1R6 Montréal Québec Canada
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Denisov AY, McManus FP, O'Flaherty DK, Noronha AM, Wilds CJ. Structural basis of interstrand cross-link repair by O6-alkylguanine DNA alkyltransferase. Org Biomol Chem 2017; 15:8361-8370. [DOI: 10.1039/c7ob02093g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Conformation of the alkylene lesion may play a role in interstrand cross-link repair by O6-alkylguanine DNA alkyltransferases.
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Affiliation(s)
- Alexey Y. Denisov
- Department of Chemistry and Biochemistry
- Concordia University
- Montréal
- Canada
| | - Francis P. McManus
- Department of Chemistry and Biochemistry
- Concordia University
- Montréal
- Canada
| | | | - Anne M. Noronha
- Department of Chemistry and Biochemistry
- Concordia University
- Montréal
- Canada
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O'Flaherty DK, Wilds CJ. O
6
-Alkylguanine DNA Alkyltransferase Repair Activity Towards Intrastrand Cross-Linked DNA is Influenced by the Internucleotide Linkage. Chem Asian J 2016; 11:576-83. [PMID: 26692563 DOI: 10.1002/asia.201501253] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Derek K. O'Flaherty
- Department of Chemistry&Biochemistry; Concordia University; 7141 Sherbrooke St. West Montréal Québec (Canada
| | - Christopher J. Wilds
- Department of Chemistry&Biochemistry; Concordia University; 7141 Sherbrooke St. West Montréal Québec (Canada
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O'Flaherty DK, Wilds CJ. Synthesis, Characterization, and Repair of a Flexible O(6) -2'-Deoxyguanosine-alkylene-O(6) -2'-deoxyguanosine Intrastrand Cross-Link. Chemistry 2015; 21:10522-9. [PMID: 26075346 DOI: 10.1002/chem.201501103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Indexed: 12/19/2022]
Abstract
Oligonucleotides tethered by an alkylene linkage between the O(6) -atoms of two consecutive 2'-deoxyguanosines, which lack a phosphodiester linkage between these residues, have been synthesized as a model system of intrastrand cross-linked (IaCL) DNA. UV thermal denaturation studies of duplexes formed between these butylene- and heptylene-linked oligonucleotides with their complementary DNA sequences revealed about 20 °C reduction in stability relative to the unmodified duplex. Circular dichroism spectra of the model IaCL duplexes displayed a signature characteristic of B-form DNA, suggesting minimal global perturbations are induced by the lesion. The model IaCL containing duplexes were investigated as substrates of O(6) -alkylguanine DNA alkyltransferase (AGT) proteins from human and E. coli (Ada-C and OGT). Human AGT was found to repair both model IaCL duplexes with greater efficiency towards the heptylene versus butylene analog adding to our knowledge of substrates this protein can repair.
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Affiliation(s)
- Derek K O'Flaherty
- Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke St. West, Montréal, Québec (Canada)
| | - Christopher J Wilds
- Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke St. West, Montréal, Québec (Canada).
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O'Flaherty DK, McManus FP, Noronha AM, Wilds CJ. Synthesis of building blocks and oligonucleotides containing {T}O4-alkylene-O4{T} interstrand cross-links. ACTA ACUST UNITED AC 2014; 55:5.13.1-19. [PMID: 25631535 DOI: 10.1002/0471142700.nc0513s55] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol describes the preparation of O(4)-thymidine-alkylene-O(4)-thymidine dimer bis-phosphoramidites and precursors for incorporation into DNA sequences to produce site-specific DNA interstrand cross-links. Linkers are introduced at the 4-position of thymidine by reacting the sodium salt of a diol with a pyrimidinyl-convertible nucleoside to produce mono-adducts, which then undergo reaction with a stoichiometric equivalent of a pyrimidinyl-convertible nucleoside under basic conditions to form O(4)-thymidine-alkylene-O(4)-thymidine dimers. Bis-phosphoramidites are incorporated into oligonucleotides by solid-phase synthesis, and mild conditions for deprotection and cleavage from the solid support are employed to prevent degradation of the thymidine modifications. Purification of these cross-linked oligonucleotides is performed by denaturing polyacrylamide gel electrophoresis. This approach allows for the preparation of cross-linked DNA substrates in quantities and purity sufficient for a wide range of biophysical experiments and biochemical studies as substrates to investigate DNA repair pathways.
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Affiliation(s)
- Derek K O'Flaherty
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec, Canada
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McManus FP, Wilds CJ. O(6) -alkylguanine-DNA alkyltransferase-mediated repair of O(4) -alkylated 2'-deoxyuridines. Chembiochem 2014; 15:1966-77. [PMID: 25087488 DOI: 10.1002/cbic.201402169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Indexed: 11/06/2022]
Abstract
O(6) -Alkylguanine-DNA alkyltransferases (AGTs) are responsible for the removal of O(6) -alkyl 2'-deoxyguanosine (dG) and O(4) -alkyl thymidine (dT) adducts from the genome. Unlike the E. coli OGT (O(6) -alkylguanine-DNA-alkyltransferase) protein, which can repair a range of O(4) -alkyl dT lesions, human AGT (hAGT) only removes methyl groups poorly. To uncover the influence of the C5 methyl group of dT on AGT repair, oligonucleotides containing O(4) -alkyl 2'-deoxyuridines (dU) were prepared. The ability of E. coli AGTs (Ada-C and OGT), human AGT, and an OGT/hAGT chimera to remove O(4) -methyl and larger adducts (4-hydroxybutyl and 7-hydroxyheptyl) from dU were examined and compared to those relating to the corresponding dT species. The absence of the C5 methyl group resulted in an increase in repair observed for the O(4) -methyl adducts by hAGT and the chimera. The chimera was proficient at repairing larger adducts at the O(4) atom of dU. There was no observed correlation between the binding affinities of the AGT homologues to adduct-containing oligonucleotides and the amounts of repair measured.
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Affiliation(s)
- Francis P McManus
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, H4B 1R6 (Canada)
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McManus FP, Khaira A, Noronha AM, Wilds CJ. Preparation of covalently linked complexes between DNA and O(6)-alkylguanine-DNA alkyltransferase using interstrand cross-linked DNA. Bioconjug Chem 2013; 24:224-33. [PMID: 23347328 DOI: 10.1021/bc300553u] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
O(6)-alkylguanine-DNA alkyltransferases (AGT) are responsible for the removal of alkylation at both the O(6) atom of guanine and O(4) atom of thymine. AGT homologues show vast substrate differences with respect to the size of the adduct and which alkylated atoms they can restore. The human AGT (hAGT) has poor capabilities for removal of methylation at the O(4) atom of thymidine, which is not the case in most homologues. No structural data are available to explain this poor hAGT repair. We prepared and characterized O(6)G-butylene-O(4)T (XLGT4) and O(6)G-heptylene-O(4)T (XLGT7) interstrand cross-linked (ICL) DNA as probes for hAGT and the Escherichia coli homologues, OGT and Ada-C, for the formation of DNA-AGT covalent complexes. XLGT7 reacted only with hAGT and did so with a cross-linking efficiency of 25%, while XLGT4 was inert to all AGT tested. The hAGT mediated repair of XLGT7 occurred slowly, on the order of hours as opposed to the repair of O(6)-methyl-2'-deoxyguanosine which requires seconds. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the repair reaction revealed the formation of a covalent complex with an observed migration in accordance with a DNA-AGT complex. The identity of this covalent complex, as determined by mass spectrometry, was composed of a heptamethylene bridge between the O(4) atom of thymidine (in an 11-mer DNA strand) to residue Cys145 of hAGT. This procedure can be applied to produce well-defined covalent complexes between AGT with DNA.
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Affiliation(s)
- Francis P McManus
- Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke St. West, Montréal, QC, Canada H4B 1R6
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McManus FP, Wilds CJ. Engineering of a O6-alkylguanine-DNA alkyltransferase chimera and repair of O4-alkyl thymidine adducts and O6-alkylene-2′-deoxyguanosine cross-linked DNA. Toxicol Res (Camb) 2013. [DOI: 10.1039/c2tx20075a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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