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Kim H, Pak Y. Isomerization Pathways of a Mismatched Base Pair of A:8OG in Free Duplex DNA. J Chem Inf Model 2024; 64:4511-4517. [PMID: 38767002 DOI: 10.1021/acs.jcim.4c00563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The A:8OG base pair (bp) is the outcome of DNA replication of the mismatched C:8OG bp. A high A:8OG bp population increases the C/G to A/T transversion mutation, which is responsible for various diseases. MutY is an important enzyme in the error-proof cycle and reverts A:8OG to C:8OG bp by cleaving adenine from the A:8OG bp. Several X-ray crystallography studies have determined the structure of MutY during the lesion scanning and lesion recognition stages. Interestingly, glycosidic bond (χ) angles of A:8OG bp in those two lesion recognition structures were found to differ, which implies that χ-torsion isomerization should occur during the lesion recognition process. In this study, as a first step to understanding this isomerization process, we characterized the intrinsic dynamic features of A:8OG in free DNAs by a free energy landscape simulation at the all-atom level. In this study, four isomerization states were assigned in the order of abundance: Aanti:8OGsyn > Aanti:8OGanti > Asyn:8OGanti ≈ Asyn:8OGsyn. Of these bp states, only 8OG in Asyn:8OGanti was located in the extrahelical space, whereas the purine bases (A and 8OG) in the other bp states remained inside the DNA helix. Also, free energy landscapes showed that the isomerization processes connecting these four bp states proceeded mostly in the intrahelical space via successive single glycosidic bond rotations of either A or 8OG.
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Affiliation(s)
- Hyeonjun Kim
- Department of Chemistry and Institute of Functional Materials, Pusan National University, Busan 46241, South Korea
| | - Youngshang Pak
- Department of Chemistry and Institute of Functional Materials, Pusan National University, Busan 46241, South Korea
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2
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Conlon S, Khuu C, Trasviña-Arenas CH, Xia T, Hamm ML, Raetz AG, David SS. Cellular Repair of Synthetic Analogs of Oxidative DNA Damage Reveals a Key Structure-Activity Relationship of the Cancer-Associated MUTYH DNA Repair Glycosylase. ACS CENTRAL SCIENCE 2024; 10:291-301. [PMID: 38435525 PMCID: PMC10906249 DOI: 10.1021/acscentsci.3c00784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 12/22/2023] [Accepted: 12/26/2023] [Indexed: 03/05/2024]
Abstract
The base excision repair glycosylase MUTYH prevents mutations associated with the oxidatively damaged base, 8-oxo-7,8-dihydroguanine (OG), by removing undamaged misincorporated adenines from OG:A mispairs. Defects in OG:A repair in individuals with inherited MUTYH variants are correlated with the colorectal cancer predisposition syndrome known as MUTYH-associated polyposis (MAP). Herein, we reveal key structural features of OG required for efficient repair by human MUTYH using structure-activity relationships (SAR). We developed a GFP-based plasmid reporter assay to define SAR with synthetically generated OG analogs in human cell lines. Cellular repair results were compared with kinetic parameters measured by adenine glycosylase assays in vitro. Our results show substrates lacking the 2-amino group of OG, such as 8OI:A (8OI = 8-oxoinosine), are not repaired in cells, despite being excellent substrates in in vitro adenine glycosylase assays, new evidence that the search and detection steps are critical factors in cellular MUTYH repair functionality. Surprisingly, modification of the O8/N7H of OG, which is the distinguishing feature of OG relative to G, was tolerated in both MUTYH-mediated cellular repair and in vitro adenine glycosylase activity. The lack of sensitivity to alterations at the O8/N7H in the SAR of MUTYH substrates is distinct from previous work with bacterial MutY, indicating that the human enzyme is much less stringent in its lesion verification. Our results imply that the human protein relies almost exclusively on detection of the unique major groove position of the 2-amino group of OG within OGsyn:Aanti mispairs to select contextually incorrect adenines for excision and thereby thwart mutagenesis. These results predict that MUTYH variants that exhibit deficiencies in OG:A detection will be severely compromised in a cellular setting. Moreover, the reliance of MUTYH on the interaction with the OG 2-amino group suggests that disrupting this interaction with small molecules may provide a strategy to develop potent and selective MUTYH inhibitors.
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Affiliation(s)
- Savannah
G. Conlon
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
- Graduate
Program in Chemistry and Chemical Biology, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Cindy Khuu
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
- Biochemistry,
Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Carlos H. Trasviña-Arenas
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
| | - Tian Xia
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
- Graduate
Program in Chemistry and Chemical Biology, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Michelle L. Hamm
- Department
of Chemistry, University of Richmond, 410 Westhampton Way, Richmond, Virginia 23173, United States
| | - Alan G. Raetz
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
- Biochemistry,
Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Sheila S. David
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
- Graduate
Program in Chemistry and Chemical Biology, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
- Biochemistry,
Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
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3
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Santos EV, Damasceno JD, Obonaga R, Rosales R, Black JA, McCulloch R, Tosi LRO. The dynamic subcellular localisation of Rad1 is cell cycle dependent in Leishmania major. Exp Parasitol 2023; 255:108639. [PMID: 37918502 DOI: 10.1016/j.exppara.2023.108639] [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: 06/13/2023] [Revised: 10/15/2023] [Accepted: 10/21/2023] [Indexed: 11/04/2023]
Abstract
The subcellular localisation of Rad1, a subunit of the Leishmania major 9-1-1 complex, remains unexplored. Herein, we reveal that Rad1 localises predominantly to the nucleus. Upon hydroxyurea treatment, the diffuse nuclear localisation of Rad1 becomes more punctate, suggesting that Rad1 is responsive to replication stress. Moreover, Rad1 localisation correlates with cell cycle progression. In the majority of G1 to early S-phase cells, Rad1 localises predominantly to the nucleus. As cells progress from late-S phase to mitosis, Rad1 relocalizes to both the nucleus and the cytoplasm in ∼90 % of cells. This pattern of distribution is different from Rad9 and Hus1, which remain nuclear throughout the cell cycle, suggesting Leishmania Rad1 may regulate 9-1-1 activities and/or perform relevant functions outside the 9-1-1 complex.
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Affiliation(s)
- Elaine V Santos
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Jeziel D Damasceno
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, UK
| | - Ricardo Obonaga
- Laboratório de Ciclo Celular, Instituto Butantan, São Paulo, SP, Brazil
| | - Roberta Rosales
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Jennifer A Black
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil; The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, UK
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, UK
| | - Luiz R O Tosi
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
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4
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Nikkel DJ, Wetmore SD. Distinctive Formation of a DNA-Protein Cross-Link during the Repair of DNA Oxidative Damage: Insights into Human Disease from MD Simulations and QM/MM Calculations. J Am Chem Soc 2023. [PMID: 37285289 DOI: 10.1021/jacs.3c01773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Reactive oxygen species damage DNA and result in health issues. The major damage product, 8-oxo-7,8-dihydroguanine (8oG), is repaired by human adenine DNA glycosylase homologue (MUTYH). Although MUTYH misfunction is associated with a genetic disorder called MUTYH-associated polyposis (MAP) and MUTYH is a potential target for cancer drugs, the catalytic mechanism required to develop disease treatments is debated in the literature. This study uses molecular dynamics simulations and quantum mechanics/molecular mechanics techniques initiated from DNA-protein complexes that represent different stages of the repair pathway to map the catalytic mechanism of the wild-type MUTYH bacterial homologue (MutY). This multipronged computational approach characterizes a DNA-protein cross-linking mechanism that is consistent with all previous experimental data and is a distinct pathway across the broad class of monofunctional glycosylase repair enzymes. In addition to clarifying how the cross-link is formed, accommodated by the enzyme, and hydrolyzed for product release, our calculations rationalize why cross-link formation is favored over immediate glycosidic bond hydrolysis, the accepted mechanism for all other monofunctional DNA glycosylases to date. Calculations on the Y126F mutant MutY highlight critical roles for active site residues throughout the reaction, while investigation of the N146S mutant rationalizes the connection between the analogous N224S MUTYH mutation and MAP. In addition to furthering our knowledge of the chemistry associated with a devastating disorder, the structural information gained about the distinctive MutY mechanism compared to other repair enzymes represents an important step for the development of specific and potent small-molecule inhibitors as cancer therapeutics.
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Affiliation(s)
- Dylan J Nikkel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
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5
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Sun J, Wang J, Chen X. Functionalization of Mesoporous Silica with a G-A-Mismatched dsDNA Chain for Efficient Identification and Selective Capturing of the MutY Protein. ACS APPLIED MATERIALS & INTERFACES 2023; 15:8884-8894. [PMID: 36757327 DOI: 10.1021/acsami.2c19257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
MUTYH adenine DNA glycosylase and its homologous protein (collectively MutY) are typical DNA glycosylases with a [4Fe4S] cluster and a helix-hairpin-helix (HhH) motif in its structure. In the present work, the binding behaviors of the MutY protein to dsDNA containing different base mismatches were investigated. The type and distribution of base mismatch in the dsDNA chain were found to influence the DNA-protein binding interaction greatly. The [4Fe4S] cluster of the MutY protein is able to identify a G-A mismatch in the dsDNA chain specifically by monitoring the anomalies of charge transport in the dsDNA chain, allowing the entrance of the identified dsDNA chain into the internal cavity of the MutY protein and the strong DNA-protein binding at the HhH motif of the protein through multiple H-bonds. The dsDNA chain with a centrally located G-A mismatch is thus functionalized on mesoporous silica (MSN) via amination reaction, and the obtained dsDNA(G-A)@MSN is used as a powerful sorbent for the selective capturing of the MutY protein from complex samples. By using 0.5% NH3·H2O (m/v) as a stripping reagent, efficient isolation of the MutY protein from different cell lines and bacteria is achieved and the recovered MutY protein is demonstrated to maintain favorable DNA adenine glycosylase activity.
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Affiliation(s)
- Jingqi Sun
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang, Liaoning 110819, China
| | - Jianhua Wang
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang, Liaoning 110819, China
| | - Xuwei Chen
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang, Liaoning 110819, China
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Mulye M, Singh MI, Jain V. From Processivity to Genome Maintenance: The Many Roles of Sliding Clamps. Genes (Basel) 2022; 13:2058. [PMID: 36360296 PMCID: PMC9690074 DOI: 10.3390/genes13112058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/03/2022] [Accepted: 11/04/2022] [Indexed: 07/30/2023] Open
Abstract
Sliding clamps play a pivotal role in the process of replication by increasing the processivity of the replicative polymerase. They also serve as an interacting platform for a plethora of other proteins, which have an important role in other DNA metabolic processes, including DNA repair. In other words, clamps have evolved, as has been correctly referred to, into a mobile "tool-belt" on the DNA, and provide a platform for several proteins that are involved in maintaining genome integrity. Because of the central role played by the sliding clamp in various processes, its study becomes essential and relevant in understanding these processes and exploring the protein as an important drug target. In this review, we provide an updated report on the functioning, interactions, and moonlighting roles of the sliding clamps in various organisms and its utilization as a drug target.
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Affiliation(s)
- Meenakshi Mulye
- Correspondence: (M.M.); (V.J.); Tel.: +91-755-269-1425 (V.J.); Fax: +91-755-269-2392 (V.J.)
| | | | - Vikas Jain
- Correspondence: (M.M.); (V.J.); Tel.: +91-755-269-1425 (V.J.); Fax: +91-755-269-2392 (V.J.)
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7
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Nunziato M, Di Maggio F, Pensabene M, Esposito MV, Starnone F, De Angelis C, Calabrese A, D’Aiuto M, Botti G, De Placido S, D’Argenio V, Salvatore F. Multi-gene panel testing increases germline predisposing mutations’ detection in a cohort of breast/ovarian cancer patients from Southern Italy. Front Med (Lausanne) 2022; 9:894358. [PMID: 36035419 PMCID: PMC9403188 DOI: 10.3389/fmed.2022.894358] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 07/15/2022] [Indexed: 11/13/2022] Open
Abstract
Breast cancer is the most common neoplasia in females worldwide, about 10% being hereditary/familial and due to DNA variants in cancer-predisposing genes, such as the highly penetrant BRCA1/BRCA2 genes. However, their variants explain up to 25% of the suspected hereditary/familial cases. The availability of NGS methodologies has prompted research in this field. With the aim to improve the diagnostic sensitivity of molecular testing, a custom designed panel of 44 genes, including also non-coding regions and 5’ and 3’ UTR regions, was set up. Here, are reported the results obtained in a cohort of 64 patients, including also few males, from Southern Italy. All patients had a positive personal and/or familial history for breast and other cancers, but tested negative to routine BRCA analysis. After obtaining their written informed consent, a genomic DNA sample/patient was used to obtain an enriched DNA library, then analyzed by NGS. Sequencing data analysis allowed the identification of pathogenic variants in 12 of tested patients (19%). Interestingly, MUTYH was the most frequently altered gene, followed by RNASEL, ATM, MSH6, MRE11A, and PALB2 genes. The reported resultsreinforce the need for enlarged molecular testing beyond BRCA genes, at least in patients with a personal and familial history, strongly suggestive for a hereditary/familial form. This gives also a hint to pursue more specific precision oncology therapy.
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Affiliation(s)
- Marcella Nunziato
- CEINGE–Biotecnologie Avanzate, Naples, Italy
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Federica Di Maggio
- CEINGE–Biotecnologie Avanzate, Naples, Italy
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Matilde Pensabene
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Maria Valeria Esposito
- CEINGE–Biotecnologie Avanzate, Naples, Italy
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Flavio Starnone
- CEINGE–Biotecnologie Avanzate, Naples, Italy
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Carmine De Angelis
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
- Department of Oncology and Hematology, Regional Reference Center for Rare Tumors, Azienda Ospedaliera Universitaria (AOU) Federico II of Naples, Naples, Italy
| | - Alessandra Calabrese
- Division of Breast Surgery, Department of Breast Disease, National Cancer Institute, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) “Fondazione G. Pascale,”Naples, Italy
| | - Massimiliano D’Aiuto
- Clinica Villa Fiorita, Aversa, Italy
- Division of Breast Oncology, National Cancer Institute, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) “Fondazione G. Pascale,”Naples, Italy
| | - Gerardo Botti
- Scientific Directorate, National Cancer Institute, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) “Fondazione G. Pascale,”Naples, Italy
| | - Sabino De Placido
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
- Department of Oncology and Hematology, Regional Reference Center for Rare Tumors, Azienda Ospedaliera Universitaria (AOU) Federico II of Naples, Naples, Italy
| | - Valeria D’Argenio
- CEINGE–Biotecnologie Avanzate, Naples, Italy
- Department of Human Sciences and Quality of Life Promotion, San Raffaele Open University, Rome, Italy
- *Correspondence: Valeria D’Argenio,
| | - Francesco Salvatore
- CEINGE–Biotecnologie Avanzate, Naples, Italy
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
- Francesco Salvatore,
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8
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Torgasheva NA, Diatlova EA, Grin IR, Endutkin AV, Mechetin GV, Vokhtantsev IP, Yudkina AV, Zharkov DO. Noncatalytic Domains in DNA Glycosylases. Int J Mol Sci 2022; 23:ijms23137286. [PMID: 35806289 PMCID: PMC9266487 DOI: 10.3390/ijms23137286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 02/04/2023] Open
Abstract
Many proteins consist of two or more structural domains: separate parts that have a defined structure and function. For example, in enzymes, the catalytic activity is often localized in a core fragment, while other domains or disordered parts of the same protein participate in a number of regulatory processes. This situation is often observed in many DNA glycosylases, the proteins that remove damaged nucleobases thus initiating base excision DNA repair. This review covers the present knowledge about the functions and evolution of such noncatalytic parts in DNA glycosylases, mostly concerned with the human enzymes but also considering some unique members of this group coming from plants and prokaryotes.
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Affiliation(s)
- Natalia A. Torgasheva
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Evgeniia A. Diatlova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
| | - Inga R. Grin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Anton V. Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Grigory V. Mechetin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Ivan P. Vokhtantsev
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
| | - Anna V. Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
- Correspondence:
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9
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Nakamura T, Yamagata Y. Visualization of mutagenic nucleotide processing by Escherichia coli MutT, a Nudix hydrolase. Proc Natl Acad Sci U S A 2022; 119:e2203118119. [PMID: 35594391 PMCID: PMC9173781 DOI: 10.1073/pnas.2203118119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/09/2022] [Indexed: 11/18/2022] Open
Abstract
Escherichia coli MutT prevents mutations by hydrolyzing mutagenic 8-oxo-2'-deoxyguanosine 5'-triphosphate (8-oxo-dGTP) in the presence of Mg2+ or Mn2+ ions. MutT is one of the most studied enzymes in the nucleoside diphosphate-linked moiety X (Nudix) hydrolase superfamily, which is widely distributed in living organisms. However, the catalytic mechanisms of most Nudix hydrolases, including two- or three-metal-ion mechanisms, are still unclear because these mechanisms are proposed using the structures mimicking the reaction states, such as substrate analog complexes. Here, we visualized the hydrolytic reaction process of MutT by time-resolved X-ray crystallography using a biological substrate, 8-oxo-dGTP, and an active metal ion, Mn2+. The reaction was initiated by soaking MutT crystals in a MnCl2 solution and stopped by freezing the crystals at various time points. In total, five types of intermediate structures were refined by investigating the time course of the electron densities in the active site as well as the anomalous signal intensities of Mn2+ ions. The structures and electron densities show that three Mn2+ ions bind to the Nudix motif of MutT and align the substrate 8-oxo-dGTP for catalysis. Accompanied by the coordination of the three Mn2+ ions, a water molecule, bound to a catalytic base, forms a binuclear Mn2+ center for nucleophilic substitution at the β-phosphorus of 8-oxo-dGTP. The reaction condition using Mg2+ also captured a structure in complex with three Mg2+ ions. This study provides the structural details essential for understanding the three-metal-ion mechanism of Nudix hydrolases and proposes that some of the Nudix hydrolases share this mechanism.
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Affiliation(s)
- Teruya Nakamura
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
- Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Yuriko Yamagata
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
- Shokei University and Shokei University Junior College, Kumamoto, 862-8678, Japan
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10
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Trasviña-Arenas CH, Demir M, Lin WJ, David SS. Structure, function and evolution of the Helix-hairpin-Helix DNA glycosylase superfamily: Piecing together the evolutionary puzzle of DNA base damage repair mechanisms. DNA Repair (Amst) 2021; 108:103231. [PMID: 34649144 DOI: 10.1016/j.dnarep.2021.103231] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
The Base Excision Repair (BER) pathway is a highly conserved DNA repair system targeting chemical base modifications that arise from oxidation, deamination and alkylation reactions. BER features lesion-specific DNA glycosylases (DGs) which recognize and excise modified or inappropriate DNA bases to produce apurinic/apyrimidinic (AP) sites and coordinate AP-site hand-off to subsequent BER pathway enzymes. The DG superfamilies identified have evolved independently to cope with a wide variety of nucleobase chemical modifications. Most DG superfamilies recognize a distinct set of structurally related lesions. In contrast, the Helix-hairpin-Helix (HhH) DG superfamily has the remarkable ability to act upon structurally diverse sets of base modifications. The versatility in substrate recognition of the HhH-DG superfamily has been shaped by motif and domain acquisitions during evolution. In this paper, we review the structural features and catalytic mechanisms of the HhH-DG superfamily and draw a hypothetical reconstruction of the evolutionary path where these DGs developed diverse and unique enzymatic features.
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Affiliation(s)
| | - Merve Demir
- Department of Chemistry, University of California, Davis, CA 95616, U.S.A
| | - Wen-Jen Lin
- Department of Chemistry, University of California, Davis, CA 95616, U.S.A
| | - Sheila S David
- Department of Chemistry, University of California, Davis, CA 95616, U.S.A..
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