1
|
Maghsoud Y, Jayasinghe-Arachchige VM, Kumari P, Cisneros GA, Liu J. Leveraging QM/MM and Molecular Dynamics Simulations to Decipher the Reaction Mechanism of the Cas9 HNH Domain to Investigate Off-Target Effects. J Chem Inf Model 2023; 63:6834-6850. [PMID: 37877218 DOI: 10.1021/acs.jcim.3c01284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR) technology is an RNA-guided targeted genome-editing tool using Cas family proteins. Two magnesium-dependent nuclease domains of the Cas9 enzyme, termed HNH and RuvC, are responsible for cleaving the target DNA (t-DNA) and nontarget DNA strands, respectively. The HNH domain is believed to determine the DNA cleavage activity of both endonuclease domains and is sensitive to complementary RNA-DNA base pairing. However, the underlying molecular mechanisms of CRISPR-Cas9, by which it rebukes or accepts mismatches, are poorly understood. Thus, investigation of the structure and dynamics of the catalytic state of Cas9 with either matched or mismatched t-DNA can provide insights into improving its specificity by reducing off-target cleavages. Here, we focus on a recently discovered catalytic-active form of the Streptococcus pyogenes Cas9 (SpCas9) and employ classical molecular dynamics and coupled quantum mechanics/molecular mechanics simulations to study two possible mechanisms of t-DNA cleavage reaction catalyzed by the HNH domain. Moreover, by designing a mismatched t-DNA structure called MM5 (C to G at the fifth position from the protospacer adjacent motif region), the impact of single-guide RNA (sgRNA) and t-DNA complementarity on the catalysis process was investigated. Based on these simulations, our calculated binding affinities, minimum energy paths, and analysis of catalytically important residues provide atomic-level details of the differences between matched and mismatched cleavage reactions. In addition, several residues exhibit significant differences in their catalytic roles for the two studied systems, including K253, K263, R820, K896, and K913.
Collapse
Affiliation(s)
- Yazdan Maghsoud
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Vindi M Jayasinghe-Arachchige
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Pratibha Kumari
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - G Andrés Cisneros
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Jin Liu
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| |
Collapse
|
2
|
Peng Z, Ma J, Christov CZ, Karabencheva-Christova T, Lehnert N, Li D. Kinetic Studies on the 2-Oxoglutarate/Fe(II)-Dependent Nucleic Acid Modifying Enzymes from the AlkB and TET Families. DNA 2023; 3:65-84. [PMID: 38698914 PMCID: PMC11065319 DOI: 10.3390/dna3020005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Nucleic acid methylations are important genetic and epigenetic biomarkers. The formation and removal of these markers is related to either methylation or demethylation. In this review, we focus on the demethylation or oxidative modification that is mediated by the 2-oxoglutarate (2-OG)/Fe(II)-dependent AlkB/TET family enzymes. In the catalytic process, most enzymes oxidize 2-OG to succinate, in the meantime oxidizing methyl to hydroxymethyl, leaving formaldehyde and generating demethylated base. The AlkB enzyme from Escherichia coli has nine human homologs (ALKBH1-8 and FTO) and the TET family includes three members, TET1 to 3. Among them, some enzymes have been carefully studied, but for certain enzymes, few studies have been carried out. This review focuses on the kinetic properties of those 2-OG/Fe(II)-dependent enzymes and their alkyl substrates. We also provide some discussions on the future directions of this field.
Collapse
Affiliation(s)
- Zhiyuan Peng
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Jian Ma
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA
| | | | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| |
Collapse
|
3
|
Maghsoud Y, Dong C, Cisneros GA. Computational Characterization of the Inhibition Mechanism of Xanthine Oxidoreductase by Topiroxostat. ACS Catal 2023; 13:6023-6043. [PMID: 37547543 PMCID: PMC10399974 DOI: 10.1021/acscatal.3c01245] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Xanthine oxidase (XO) is a member of the molybdopterin-containing enzyme family. It interconverts xanthine to uric acid as the last step of purine catabolism in the human body. The high uric acid concentration in the blood directly leads to human diseases like gout and hyperuricemia. Therefore, drugs that inhibit the biosynthesis of uric acid by human XO have been clinically used for many years to decrease the concentration of uric acid in the blood. In this study, the inhibition mechanism of XO and a new promising drug, topiroxostat (code: FYX-051), is investigated by employing molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) calculations. This drug has been reported to act as both a noncovalent and covalent inhibitor and undergoes a stepwise inhibition by all its hydroxylated metabolites, which include 2-hydroxy-FYX-051, dihydroxy-FYX-051, and trihydroxy-FYX-051. However, the detailed mechanism of inhibition of each metabolite remains elusive and can be useful for designing more effective drugs with similar inhibition functions. Hence, herein we present the computational investigation of the structural and dynamical effects of FYX-051 and the calculated reaction mechanism for all of the oxidation steps catalyzed by the molybdopterin center in the active site. Calculated results for the proposed reaction mechanisms for each metabolite's inhibition reaction in the enzyme's active site, binding affinities, and the noncovalent interactions with the surrounding amino acid residues are consistent with previously reported experimental findings. Analysis of the noncovalent interactions via energy decomposition analysis (EDA) and noncovalent interaction (NCI) techniques suggests that residues L648, K771, E802, R839, L873, R880, R912, F914, F1009, L1014, and A1079 can be used as key interacting residues for further hybrid-type inhibitor development.
Collapse
Affiliation(s)
- Yazdan Maghsoud
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Chao Dong
- Department of Chemistry and Physics, The University of Texas Permian Basin, Odessa, Texas 79762, United States
| | - G Andrés Cisneros
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States; Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| |
Collapse
|
4
|
Chen Y, Zhou P, Deng Y, Cai X, Sun M, Sun Y, Wu D. ALKBH5-mediated m 6 A demethylation of TIRAP mRNA promotes radiation-induced liver fibrosis and decreases radiosensitivity of hepatocellular carcinoma. Clin Transl Med 2023; 13:e1198. [PMID: 36792369 PMCID: PMC9931500 DOI: 10.1002/ctm2.1198] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/19/2023] [Accepted: 01/29/2023] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND Radiation-induced hepatic stellate cell (HSC) activation promotes radiation-induced liver fibrosis (RILF), a complication for hepatocellular carcinoma (HCC) radiotherapy. The demethylase alpha-ketoglutarate-dependent dioxygenase alkB homolog 5 (ALKBH5) decreases N6-methyladenylate methylation (m6 A) modification of RNA, while its role in regulating RILF pathogenesis and HCC radiosensitivity remains unknown. METHODS Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-sequencing (RNA-seq) were used to screen target genes regulated by ALKBH5. HSC with altered ALKBH5 expression was used to assess irradiation-induced HSC activation and the effect of HSC on recruitment and polarisation of monocytes. Key cytokines in medium from irradiated HSC-educated monocytes were identified by cytokine array detection. The effects of blocking ALKBH5 and key cytokines on RILF and HCC radiosensitivity were also evaluated. RESULTS Radiation-induced ALKBH5 expression in HSC mediated m6 A demethylation of toll-interleukin 1 receptor domain containing adaptor protein (TIRAP) mRNA and activated its downstream NF-κB and JNK/Smad2 pathways to promote HSC activation. Additionally, ALKBH5 regulated CCL5 secretion by irradiated HSC to promote monocyte recruitment and M2 macrophage polarisation. Notably, polarised monocytes secreted CCL20 to up-regulate ALKBH5 expression in HSC, and reduce HCC radiosensitivity by activating ALKBH5/TIRAP axis in HCC cells. ALKBH5 knockdown-combined CCR6 (CCL20 receptor) inhibitor significantly alleviated RILF and improved HCC radiosensitivity in mice. HCC patients with high ALKBH5 and TIRAP expression were prone to radiation-induced liver injury and poor tumour response to radiotherapy. CONCLUSIONS Collectively, irradiation up-regulates ALKBH5 in HSC to mediate monocyte recruitment and M2 polarisation and form positive feedback to promote RILF and reduce HCC radiosensitivity. The dual roles of ALKBH5 as a microenvironmental regulator and radiosensitisation target provide new ideas for RILF prevention and radiosensitisation of HCC.
Collapse
Affiliation(s)
- Yuhan Chen
- Department of Radiation OncologyNanfang Hospital, Southern Medical UniversityGuangzhouChina
| | - Peitao Zhou
- Department of Radiation OncologyNanfang Hospital, Southern Medical UniversityGuangzhouChina
| | - Yixun Deng
- The First School of Clinical MedicineSouthern Medical UniversityGuangzhouChina
| | - Xinni Cai
- The First School of Clinical MedicineSouthern Medical UniversityGuangzhouChina
| | - Mingrui Sun
- The First School of Clinical MedicineSouthern Medical UniversityGuangzhouChina
| | - Yining Sun
- Department of Radiation OncologyNanfang Hospital, Southern Medical UniversityGuangzhouChina
| | - Dehua Wu
- Department of Radiation OncologyNanfang Hospital, Southern Medical UniversityGuangzhouChina
| |
Collapse
|
5
|
Wojdyla Z, Borowski T. Properties of the Reactants and Their Interactions within and with the Enzyme Binding Cavity Determine Reaction Selectivities. The Case of Fe(II)/2-Oxoglutarate Dependent Enzymes. Chemistry 2022; 28:e202104106. [PMID: 34986268 DOI: 10.1002/chem.202104106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 12/12/2022]
Abstract
Fe(II)/2-oxoglutarate dependent dioxygenases (ODDs) share a double stranded beta helix (DSBH) fold and utilise a common reactive intermediate, ferryl species, to catalyse oxidative transformations of substrates. Despite the structural similarities, ODDs accept a variety of substrates and facilitate a wide range of reactions, that is hydroxylations, desaturations, (oxa)cyclisations and ring rearrangements. In this review we present and discuss the factors contributing to the observed (regio)selectivities of ODDs. They span from inherent properties of the reactants, that is, substrate molecule and iron cofactor, to the interactions between the substrate and the enzyme's binding cavity; the latter can counterbalance the effect of the former. Based on results of both experimental and computational studies dedicated to ODDs, we also line out the properties of the reactants which promote reaction outcomes other than the "default" hydroxylation. It turns out that the reaction selectivity depends on a delicate balance of interactions between the components of the investigated system.
Collapse
Affiliation(s)
- Zuzanna Wojdyla
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Niezapominajek 8, 30239 Krakow, Poland
| | - Tomasz Borowski
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Niezapominajek 8, 30239 Krakow, Poland
| |
Collapse
|
6
|
Berger MB, Walker AR, Vázquez-Montelongo EA, Cisneros GA. Computational investigations of selected enzymes from two iron and α-ketoglutarate-dependent families. Phys Chem Chem Phys 2021; 23:22227-22240. [PMID: 34586107 PMCID: PMC8516722 DOI: 10.1039/d1cp03800a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
DNA alkylation is used as the key epigenetic mark in eukaryotes, however, most alkylation in DNA can result in deleterious effects. Therefore, this process needs to be tightly regulated. The enzymes of the AlkB and Ten-Eleven Translocation (TET) families are members of the Fe and alpha-ketoglutarate-dependent superfamily of enzymes that are tasked with dealkylating DNA and RNA in cells. Members of these families span all species and are an integral part of transcriptional regulation. While both families catalyze oxidative dealkylation of various bases, each has specific preference for alkylated base type as well as distinct catalytic mechanisms. This perspective aims to provide an overview of computational work carried out to investigate several members of these enzyme families including AlkB, ALKB Homolog 2, ALKB Homolog 3 and Ten-Eleven Translocate 2. Insights into structural details, mutagenesis studies, reaction path analysis, electronic structure features in the active site, and substrate preferences are presented and discussed.
Collapse
Affiliation(s)
- Madison B Berger
- Department of Chemistry, University of North Texas, Denton, Texas, 76201, USA.
| | - Alice R Walker
- Department of Chemistry, Wayne State University, Detroit, Michigan, 48202, USA
| | | | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, Texas, 76201, USA.
| |
Collapse
|
7
|
Hix MA, Leddin EM, Cisneros GA. Combining Evolutionary Conservation and Quantum Topological Analyses To Determine Quantum Mechanics Subsystems for Biomolecular Quantum Mechanics/Molecular Mechanics Simulations. J Chem Theory Comput 2021; 17:4524-4537. [PMID: 34087064 PMCID: PMC8477969 DOI: 10.1021/acs.jctc.1c00313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Selection of residues and other molecular fragments for inclusion in the quantum mechanics (QM) region for QM/molecular mechanics (MM) simulations is an important step for these calculations. Here, we present an approach that combines protein sequence/structure evolution and electron localization function (ELF) analyses. The combination of these two analyses allows the determination of whether a residue needs to be included in the QM subsystem or can be represented by the MM environment. We have applied this approach on two systems previously investigated by QM/MM simulations, 4-oxalocrotonate tautomerase (4OT) and ten-eleven translocation-2 (TET2), that provide examples where fragments may or may not need to be included in the QM subsystem. Subsequently, we present the use of this approach to determine the appropriate QM subsystem to calculate the minimum energy path (MEP) for the reaction catalyzed by human DNA polymerase λ (Polλ) with a third cation in the active site. Our results suggest that the combination of protein evolutionary and ELF analyses provides insights into residue/molecular fragment selection for QM/MM simulations.
Collapse
Affiliation(s)
- Mark A Hix
- Department of Chemistry, University of North Texas, Denton, Texas 76201, United States
| | - Emmett M Leddin
- Department of Chemistry, University of North Texas, Denton, Texas 76201, United States
| | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, Texas 76201, United States
| |
Collapse
|
8
|
Wang J, Wang X, Ouyang Q, Liu W, Shan J, Tan H, Li X, Chen G. N-Nitrosation Mechanism Catalyzed by Non-heme Iron-Containing Enzyme SznF Involving Intramolecular Oxidative Rearrangement. Inorg Chem 2021; 60:7719-7731. [PMID: 34004115 DOI: 10.1021/acs.inorgchem.1c00057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The non-heme iron-dependent enzyme SznF catalyzes a critical N-nitrosation step during the N-nitrosourea pharmacophore biosynthesis in streptozotocin. The intramolecular oxidative rearrangement process is known to proceed at the FeII-containing active site in the cupin domain of SznF, but its mechanism has not been elucidated to date. In this study, based on the density functional theory calculations, a unique mechanism was proposed for the N-nitrosation reaction catalyzed by SznF in which a four-electron oxidation process is accomplished through a series of complicated electron transferring between the iron center and substrate to bypass the high-valent FeIV═O species. In the catalytic reaction pathway, the O2 binds to the iron center and attacks on the substrate to form the peroxo bridge intermediate by obtaining two electrons from the substrate exclusively. Then, instead of cleaving the peroxo bridge, the Cε-Nω bond of the substrate is homolytically cleaved first to form a carbocation intermediate, which polarizes the peroxo bridge and promotes its heterolysis. After O-O bond cleavage, the following reaction steps proceed effortlessly so that the N-nitrosation is accomplished without NO exchange among reaction species.
Collapse
Affiliation(s)
- Junkai Wang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xixi Wang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Qingwen Ouyang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wei Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jiankai Shan
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Hongwei Tan
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xichen Li
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Guangju Chen
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
9
|
Chaturvedi SS, Ramanan R, Hu J, Hausinger RP, Christov CZ. Atomic and Electronic Structure Determinants Distinguish between Ethylene Formation and l-Arginine Hydroxylation Reaction Mechanisms in the Ethylene-Forming Enzyme. ACS Catal 2021. [DOI: 10.1021/acscatal.0c03349] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Shobhit S. Chaturvedi
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Rajeev Ramanan
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | | | | | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| |
Collapse
|
10
|
Waheed S, Ramanan R, Chaturvedi SS, Lehnert N, Schofield CJ, Christov CZ, Karabencheva-Christova TG. Role of Structural Dynamics in Selectivity and Mechanism of Non-heme Fe(II) and 2-Oxoglutarate-Dependent Oxygenases Involved in DNA Repair. ACS CENTRAL SCIENCE 2020; 6:795-814. [PMID: 32490196 PMCID: PMC7256942 DOI: 10.1021/acscentsci.0c00312] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Indexed: 05/08/2023]
Abstract
AlkB and its human homologue AlkBH2 are Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenases that repair alkylated DNA bases occurring as a consequence of reactions with mutagenic agents. We used molecular dynamics (MD) and combined quantum mechanics/molecular mechanics (QM/MM) methods to investigate how structural dynamics influences the selectivity and mechanisms of the AlkB- and AlkBH2-catalyzed demethylation of 3-methylcytosine (m3C) in single (ssDNA) and double (dsDNA) stranded DNA. Dynamics studies reveal the importance of the flexibility in both the protein and DNA components in determining the preferences of AlkB for ssDNA and of AlkBH2 for dsDNA. Correlated motions, including of a hydrophobic β-hairpin, are involved in substrate binding in AlkBH2-dsDNA. The calculations reveal that 2OG rearrangement prior to binding of dioxygen to the active site Fe is preferred over a ferryl rearrangement to form a catalytically productive Fe(IV)=O intermediate. Hydrogen atom transfer proceeds via a σ-channel in AlkBH2-dsDNA and AlkB-dsDNA; in AlkB-ssDNA, there is a competition between σ- and π-channels, implying that the nature of the complexed DNA has potential to alter molecular orbital interactions during the substrate oxidation. Our results reveal the importance of the overall protein-DNA complex in determining selectivity and how the nature of the substrate impacts the mechanism.
Collapse
Affiliation(s)
- Sodiq
O. Waheed
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Rajeev Ramanan
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Shobhit S. Chaturvedi
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Nicolai Lehnert
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Christopher J. Schofield
- The
Chemistry Research Laboratory, The Department of Chemistry, Mansfield
Road, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Christo Z. Christov
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | | |
Collapse
|
11
|
Chaturvedi S, Ramanan R, Lehnert N, Schofield CJ, Karabencheva-Christova TG, Christov CZ. Catalysis by the Non-Heme Iron(II) Histone Demethylase PHF8 Involves Iron Center Rearrangement and Conformational Modulation of Substrate Orientation. ACS Catal 2020; 10:1195-1209. [PMID: 31976154 PMCID: PMC6970271 DOI: 10.1021/acscatal.9b04907] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/10/2019] [Indexed: 02/07/2023]
Abstract
PHF8 (KDM7B) is a human non-heme 2-oxoglutarate (2OG) JmjC domain oxygenase that catalyzes the demethylation of the di/mono-Nε-methylated K9 residue of histone H3. Altered PHF8 activity is linked to genetic diseases and cancer; thus, it is an interesting target for epigenetic modulation. We describe the use of combined quantum mechanics/molecular mechanics (QM/MM) and molecular dynamics (MD) simulations to explore the mechanism of PHF8, including dioxygen activation, 2OG binding modes, and substrate demethylation steps. A PHF8 crystal structure manifests the 2OG C-1 carboxylate bound to iron in a nonproductive orientation, i.e., trans to His247. A ferryl-oxo intermediate formed by activating dioxygen bound to the vacant site in this complex would be nonproductive, i.e., "off-line" with respect to reaction with Nε-methylated K9. We show rearrangement of the "off-line" ferryl-oxo intermediate to a productive "in-line" geometry via a solvent exchange reaction (called "ferryl-flip") is energetically unfavorable. The calculations imply that movement of the 2OG C-1 carboxylate prior to dioxygen binding at a five-coordination stage in catalysis proceeds with a low barrier, suggesting that two possible 2OG C-1 carboxylate geometries can coexist at room temperature. We explored alternative mechanisms for hydrogen atom transfer and show that second sphere interactions orient the Nε-methylated lysine in a conformation where hydrogen abstraction from a methyl C-H bond is energetically more favorable than hydrogen abstraction from the N-H bond of the protonated Nε-methyl group. Using multiple HAT reaction path calculations, we demonstrate the crucial role of conformational flexibility in effective hydrogen transfer. Subsequent hydroxylation occurs through a rebound mechanism, which is energetically preferred compared to desaturation, due to second sphere interactions. The overall mechanistic insights reveal the crucial role of iron-center rearrangement, second sphere interactions, and conformational flexibility in PHF8 catalysis and provide knowledge useful for the design of mechanism-based PHF8 inhibitors.
Collapse
Affiliation(s)
- Shobhit
S. Chaturvedi
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Rajeev Ramanan
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Nicolai Lehnert
- Department
of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | | | - Christo Z. Christov
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| |
Collapse
|
12
|
Leddin EM, Cisneros GA. Comparison of DNA and RNA substrate effects on TET2 structure. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 117:91-112. [PMID: 31564308 DOI: 10.1016/bs.apcsb.2019.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ten-eleven translocation (TET) enzymes can perform the stepwise oxidation of 5-methylcytosine (5mC) to 5-carboxylcytosine on both single-stranded (ss) and double-stranded (ds) DNA and RNA. It has been established that TET2 has a preference for ds DNA substrates, but it can catalyze the oxidation reaction on both ssDNA and RNA. The reasons for this substrate preference have been investigated for only a substrate 5mC ribonucleotide in a DNA strand, but not other nucleic acid configurations (Biochemistry58 (2019) 411). We performed molecular dynamics simulations on TET2 with various ss and ds substrates in order to better understand the structural and dynamical reasons for TET2's preference to act on ds DNA. Our simulations show that substrates that have a ribonucleotide experience several disruptions in their overall backbone shape, hydrogen bonding character, and non-bonded interactions. These differences appear to lead to the instability of ribonucleotide in the active site, and provide further rational for TET2's experimental behavior.
Collapse
Affiliation(s)
- Emmett M Leddin
- Department of Chemistry, University of North Texas, Denton, TX, United States
| | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, TX, United States
| |
Collapse
|
13
|
Herr CQ, Macomber L, Kalliri E, Hausinger RP. Glutarate L-2-hydroxylase (CsiD/GlaH) is an archetype Fe(II)/2-oxoglutarate-dependent dioxygenase. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 117:63-90. [PMID: 31564307 DOI: 10.1016/bs.apcsb.2019.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Escherichia coli gene initially named ygaT is located adjacent to lhgO, encoding L-2-hydroxyglutarate oxidase/dehydrogenase, and the gabDTP gene cluster, utilized for γ-aminobutyric acid (GABA) metabolism. Because this gene is transcribed specifically during periods of carbon starvation, it was renamed csiD for carbon starvation induced. The CsiD protein was structurally characterized and shown to possess a double-stranded ß-helix fold, characteristic of a large family of non-heme Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenases. Consistent with a role in producing the substrate for LhgO, CsiD was shown to be a glutarate L-2-hydroxylase. We review the kinetic and structural properties of glutarate L-2-hydroxylase from E. coli and other species, and we propose a catalytic mechanism for this archetype 2OG-dependent hydroxylase. Glutarate can be derived from l-lysine within the cell, with the gabDT genes exhibiting expanded reactivities beyond those known for GABA metabolism. The complete CsiD-containing pathway provides a means for the cell to obtain energy from the metabolism of l-lysine during periods of carbon starvation. To reflect the role of this protein in the cell, a renaming of csiD to glaH has been proposed.
Collapse
Affiliation(s)
- Caitlyn Q Herr
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Lee Macomber
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Efthalia Kalliri
- Department of Chemistry, Michigan State University, East Lansing, MI, United States
| | - Robert P Hausinger
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States; Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| |
Collapse
|
14
|
Torabifard H, Cisneros GA. Insight into wild-type and T1372E TET2-mediated 5hmC oxidation using ab initio QM/MM calculations. Chem Sci 2018; 9:8433-8445. [PMID: 30542593 PMCID: PMC6244454 DOI: 10.1039/c8sc02961j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/11/2018] [Indexed: 12/22/2022] Open
Abstract
Ten-eleven translocation 2 (TET2) is an Fe/α-ketoglutarate (α-KG) dependent enzyme that dealkylates 5-methylcytosine (5mC). The reaction mechanism involves a series of three sequential oxidations that convert 5mC to 5-hydroxy-methylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). Our previous biochemical and computational studies uncovered an active site scaffold that is required for wild-type (WT) stepwise oxidation (Nat. Chem. Bio., 13, 181). We showed that the mutation of a single residue, T1372 to some amino acids, such as Glu, can impact the iterative oxidation steps and stop the oxidation of 5hmC to 5fC/caC. However, the source of the stalling at the first oxidation step by some mutant TET proteins still remains unclear. Here, we studied the catalytic mechanism of oxidation of 5hmC to 5fC by WT and T1372E TET2 using an ab initio quantum mechanical/molecular mechanical (QM/MM) approach. Our results suggest that the rate limiting step for WT TET2 involves a hydrogen atom abstraction from the hydroxyl group of 5hmC by the ferryl moiety in the WT. By contrast, our calculations for the T1372E mutant indicate that the rate limiting step for this variant corresponds to a second proton abstraction and the calculated barrier is almost twice as large as for WT TET2. Our results suggest that the large barrier for the 5hmC to 5fC oxidation in this mutant is due (at least in part) to the unfavorable orientation of the substrate in the active site. Combined electron localization function (ELF) and non-covalent interaction (NCI) analyses provide a qualitative description of the evolution of the electronic structure of the active site along the reaction path. Energy decomposition analysis (EDA) has been performed on the WT to investigate the impact of each MM residue on catalytic activity.
Collapse
Affiliation(s)
- Hedieh Torabifard
- Department of Chemistry , Wayne State University , Detroit , MI 48202 , USA
| | - G Andrés Cisneros
- Department of Chemistry , University of North Texas , Denton , TX 76203 , USA .
| |
Collapse
|
15
|
Vázquez-Montelongo EA, Vázquez-Cervantes JE, Cisneros GA. Polarizable ab initio QM/MM Study of the Reaction Mechanism of N- tert-Butyloxycarbonylation of Aniline in [EMIm][BF₄]. Molecules 2018; 23:E2830. [PMID: 30384470 PMCID: PMC6278528 DOI: 10.3390/molecules23112830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 10/27/2018] [Accepted: 10/29/2018] [Indexed: 12/25/2022] Open
Abstract
N-t e r t-butoxycarbonylation of amines in solution (water, organic solvents, or ionic liquids) is a common reaction for the preparation of drug molecules. To understand the reaction mechanism and the role of the solvent, quantum mechanical/molecular mechanical simulations using a polarizable multipolar force field with long⁻range electrostatic corrections were used to optimize the minimum energy paths (MEPs) associated with various possible reaction mechanisms employing the nudged elastic band (NEB) and the quadratic string method (QSM). The calculated reaction energies and energy barriers were compared with the corresponding gas-phase and dichloromethane results. Complementary Electron Localization Function (ELF)/NCI analyses provide insights on the critical structures along the MEP. The calculated results suggest the most likely path involves a sequential mechanism with the rate⁻limiting step corresponding to the nucleophilic attack of the aniline, followed by proton transfer and the release of CO 2 without the direct involvement of imidazolium cations as catalysts.
Collapse
Affiliation(s)
| | | | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, TX 76201, USA.
- The Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas, Denton, TX 76201, USA.
| |
Collapse
|
16
|
Song X, Lu J, Lai W. Mechanistic insights into dioxygen activation, oxygen atom exchange and substrate epoxidation by AsqJ dioxygenase from quantum mechanical/molecular mechanical calculations. Phys Chem Chem Phys 2018; 19:20188-20197. [PMID: 28726913 DOI: 10.1039/c7cp02687k] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herein, we use in-protein quantum mechanical/molecular mechanical (QM/MM) calculations to elucidate the mechanism of dioxygen activation, oxygen atom exchange and substrate epoxidation processes by AsqJ, an FeII/α-ketoglutarate-dependent dioxygenase (α-KGD) using a 2-His-1-Asp facial triad. Our results demonstrated that the whole reaction proceeds through a quintet surface. The dioxygen activation by AsqJ leads to a quintet penta-coordinated FeIV-oxo species, which has a square pyramidal geometry with the oxo group trans to His134. This penta-coordinated FeIV-oxo species is not the reactive one in the substrate epoxidation reaction since its oxo group is pointing away from the target C[double bond, length as m-dash]C bond. Instead, it can undergo the oxo group isomerization followed by water binding or the water binding followed by oxygen atom exchange to form the reactive hexa-coordinated FeIV-oxo species with the oxo group trans to His211. The calculated parameters of Mössbauer spectra for this hexa-coordinated FeIV-oxo intermediate are in excellent agreement with the experimental values, suggesting that it is most likely the experimentally trapped species. The calculated energetics indicated that the rate-limiting step is the substrate C[double bond, length as m-dash]C bond activation. This work improves our understanding of the dioxygen activation by α-KGD and provides important structural information about the reactive FeIV-oxo species.
Collapse
Affiliation(s)
- Xudan Song
- Department of Chemistry, Renmin University of China, Beijing, 100872, China.
| | | | | |
Collapse
|
17
|
Corbella M, Voityuk AA, Curutchet C. How abasic sites impact hole transfer dynamics in GC-rich DNA sequences. Phys Chem Chem Phys 2018; 20:23123-23131. [DOI: 10.1039/c8cp03572e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hole transfer dynamics through GC-rich DNA duplexes containing abasic sites is strongly modulated by the nature of the unpaired nucleobase.
Collapse
Affiliation(s)
- Marina Corbella
- Departament de Farmàcia i Tecnologia Farmacèutica i Fisicoquímica and Institut de Química Teòrica i Computacional (IQTC-UB)
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - Alexander A. Voityuk
- Institució Catalana de Recerca i Estudis Avançats (ICREA)
- 08010 Barcelona
- Spain
- Institut de Química Computacional i Catàlisi and Departament de Química
- Universitat de Girona
| | - Carles Curutchet
- Departament de Farmàcia i Tecnologia Farmacèutica i Fisicoquímica and Institut de Química Teòrica i Computacional (IQTC-UB)
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| |
Collapse
|
18
|
Torabifard H, Cisneros GA. Computational investigation of O 2 diffusion through an intra-molecular tunnel in AlkB; influence of polarization on O 2 transport. Chem Sci 2017; 8:6230-6238. [PMID: 28989656 PMCID: PMC5628400 DOI: 10.1039/c7sc00997f] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/03/2017] [Indexed: 12/13/2022] Open
Abstract
E. Coli AlkB catalyzes the direct dealkylation of various alkylated bases in damaged DNA. The diffusion of molecular oxygen to the active site in AlkB is an essential step for the oxidative dealkylation activity. Despite detailed studies on the stepwise oxidation mechanism of AlkB, there is no conclusive picture of how O2 molecules reach the active site of the protein. Yu et al. (Nature, 439, 879) proposed the existence of an intra-molecular tunnel based on their initial crystal structures of AlkB. We have employed computational simulations to investigate possible migration pathways inside AlkB for O2 molecules. Extensive molecular dynamics (MD) simulations, including explicit ligand sampling and potential of mean force (PMF) calculations, have been performed to provide a microscopic description of the O2 delivery pathway in AlkB. Analysis of intra-molecular tunnels using the CAVER software indicates two possible pathways for O2 to diffuse into the AlkB active site. Explicit ligand sampling simulations suggests that only one of these tunnels provides a viable route. The free energy path for an oxygen molecule to travel along each of these tunnels has been determined with AMBER and AMOEBA. Both PMFs indicate passive transport of O2 from the surface of the protein. However, the inclusion of explicit polarization shows a very large barrier for diffusion of the co-substrate out of the active site, compared with the non-polarizable potential. In addition, our results suggest that the mutation of a conserved residue along the tunnel, Y178, has dramatic effects on the dynamics of AlkB and on the transport of O2 along the tunnel.
Collapse
Affiliation(s)
- Hedieh Torabifard
- Department of Chemistry , Wayne State University , Detroit , MI 48202 , USA
| | - G Andrés Cisneros
- Department of Chemistry , University of North Texas , Denton , TX 76203 , USA .
| |
Collapse
|
19
|
Faponle AS, Seebeck FP, de Visser SP. Sulfoxide Synthase versus Cysteine Dioxygenase Reactivity in a Nonheme Iron Enzyme. J Am Chem Soc 2017; 139:9259-9270. [PMID: 28602090 DOI: 10.1021/jacs.7b04251] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sulfoxide synthase EgtB represents a unique family of nonheme iron enzymes that catalyze the formation of a C-S bond between N-α-trimethyl histidine and γ-glutamyl cysteine, which is the key step in the biosynthesis of ergothioneine, an important amino acid related to aging. A controversy has arisen regarding its catalytic mechanism related to the function of the active-site Tyr377 residue. The biosynthesis of ergothioneine in EgtB shows structural similarities to cysteine dioxygenase which transfers two oxygen atoms to the thiolate group of cysteine. The question, therefore, is how do EgtB enzymes catalyze the C-S bond-formation reaction, while also preventing a dioxygenation of its cysteinate substrate? In this work we present a quantum mechanics/molecular mechanics study into the mechanism of sulfoxide synthase enzymes as compared to cysteine dioxygenase enzymes and present pathways for both reaction channels in EgtB. We show that EgtB contains a conserved tyrosine residue that reacts via proton-coupled electron transfer with the iron(III)-superoxo species and creates an iron(III)-hydroperoxo intermediate, thereby preventing the possible thiolate dioxygenation side reaction. The nucleophilic C-S bond-formation step happens subsequently concomitant to relay of the proton of the iron(II)-hydroperoxo back to Tyr377. This is the rate-determining step in the reaction cycle and is followed by hydrogen-atom transfer from the CE1-H group of trimethyl histidine substrate to iron(II)-superoxo. In the final step, a quick and almost barrierless sulfoxidation leads to the sulfoxide product complexes. The work highlights a unique machinery and active-site setup of the enzyme that drives the sulfoxide synthase reaction.
Collapse
Affiliation(s)
- Abayomi S Faponle
- The Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Florian P Seebeck
- Department for Chemistry, University of Basel , St. Johanns-Ring 19, Basel 4056, Switzerland
| | - Sam P de Visser
- The Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| |
Collapse
|
20
|
Walker AR, Silvestrov P, Müller TA, Podolsky RH, Dyson G, Hausinger RP, Cisneros GA. ALKBH7 Variant Related to Prostate Cancer Exhibits Altered Substrate Binding. PLoS Comput Biol 2017; 13:e1005345. [PMID: 28231280 PMCID: PMC5322872 DOI: 10.1371/journal.pcbi.1005345] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/04/2017] [Indexed: 11/18/2022] Open
Abstract
The search for prostate cancer biomarkers has received increased attention and several DNA repair related enzymes have been linked to this dysfunction. Here we report a targeted search for single nucleotide polymorphisms (SNPs) and functional impact characterization of human ALKBH family dioxygenases related to prostate cancer. Our results uncovered a SNP of ALKBH7, rs7540, which is associated with prostate cancer disease in a statistically significantly manner in two separate cohorts, and maintained in African American men. Comparisons of molecular dynamics (MD) simulations on the wild-type and variant protein structures indicate that the resulting alteration in the enzyme induces a significant structural change that reduces ALKBH7’s ability to bind its cosubstrate. Experimental spectroscopy studies with purified proteins validate our MD predictions and corroborate the conclusion that this cancer-associated mutation affects productive cosubstrate binding in ALKBH7. Improvements in personalized DNA sequencing have led to an increased interest in targeted biomarkers for therapeutic and diagnostic purposes. In this work, we report on a new biomarker for prostate cancer found through a targeted search for single nucleotide polymorphisms (SNPs) of the genes encoding human ALKBH family dioxygenases. Our results uncovered rs7540, which leads to a missense mutation in ALKBH7. Comparative molecular dynamics simulations on the wild type and SNP variant of the protein show that the mutation elicits a structural change that dramatically decreases ALKBH7’s affinity for its cosubstrate. This prediction is confirmed by experimental UV-Vis spectroscopy. Taken together, these results give important insights into a novel prostate-cancer related SNP and its impact on the structure and function of ALKBH7.
Collapse
Affiliation(s)
- Alice R. Walker
- Department of Chemistry, Wayne State University, Detroit, MI, United States of America
| | - Pavel Silvestrov
- Department of Chemistry, Wayne State University, Detroit, MI, United States of America
| | - Tina A. Müller
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States of America
| | - Robert H. Podolsky
- Wayne State University Department of Family Medicine and Public Health Sciences, Wayne State University, Detroit, MI, United States of America
| | - Gregory Dyson
- Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States of America
| | - Robert P. Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States of America
| | - Gerardo Andrés Cisneros
- Department of Chemistry, Wayne State University, Detroit, MI, United States of America
- * E-mail:
| |
Collapse
|
21
|
Mutations along a TET2 active site scaffold stall oxidation at 5-hydroxymethylcytosine. Nat Chem Biol 2016; 13:181-187. [PMID: 27918559 DOI: 10.1038/nchembio.2250] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 09/29/2016] [Indexed: 12/16/2022]
Abstract
Ten-eleven translocation (TET) enzymes catalyze stepwise oxidation of 5-methylcytosine (mC) to yield 5-hydroxymethylcytosine (hmC) and the rarer bases 5-formylcytosine (fC) and 5-carboxylcytosine (caC). Stepwise oxidation obscures how each individual base forms and functions in epigenetic regulation, and prompts the question of whether TET enzymes primarily serve to generate hmC or are adapted to produce fC and caC as well. By mutating a single, conserved active site residue in human TET2, Thr1372, we uncovered enzyme variants that permit oxidation to hmC but largely eliminate fC and caC. Biochemical analyses, combined with molecular dynamics simulations, elucidated an active site scaffold that is required for wild-type (WT) stepwise oxidation and that, when perturbed, explains the mutants' hmC-stalling phenotype. Our results suggest that the TET2 active site is shaped to enable higher-order oxidation and provide the first TET variants that could be used to probe the biological functions of hmC separately from fC and caC.
Collapse
|
22
|
Protein effects in non-heme iron enzyme catalysis: insights from multiscale models. J Biol Inorg Chem 2016; 21:645-57. [DOI: 10.1007/s00775-016-1374-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/20/2016] [Indexed: 01/09/2023]
|
23
|
Abstract
Mononuclear non-heme Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenases comprise a large family of enzymes that utilize an Fe(IV)-oxo intermediate to initiate diverse oxidative transformations with important biological roles. Here, four of the major types of Fe(II)/2OG-dependent reactions are detailed: hydroxylation, halogenation, ring formation, and desaturation. In addition, an atypical epimerization reaction is described. Studies identifying several key intermediates in catalysis are concisely summarized, and the proposed mechanisms are explained. In addition, a variety of other transformations catalyzed by selected family members are briefly described to further highlight the chemical versatility of these enzymes.
Collapse
Affiliation(s)
- Salette Martinez
- Departments of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824
| | - Robert P Hausinger
- Departments of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824; Departments of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824.
| |
Collapse
|
24
|
Fedeles BI, Singh V, Delaney JC, Li D, Essigmann JM. The AlkB Family of Fe(II)/α-Ketoglutarate-dependent Dioxygenases: Repairing Nucleic Acid Alkylation Damage and Beyond. J Biol Chem 2015; 290:20734-20742. [PMID: 26152727 DOI: 10.1074/jbc.r115.656462] [Citation(s) in RCA: 272] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The AlkB family of Fe(II)- and α-ketoglutarate-dependent dioxygenases is a class of ubiquitous direct reversal DNA repair enzymes that remove alkyl adducts from nucleobases by oxidative dealkylation. The prototypical and homonymous family member is an Escherichia coli "adaptive response" protein that protects the bacterial genome against alkylation damage. AlkB has a wide variety of substrates, including monoalkyl and exocyclic bridged adducts. Nine mammalian AlkB homologs exist (ALKBH1-8, FTO), but only a subset functions as DNA/RNA repair enzymes. This minireview presents an overview of the AlkB proteins including recent data on homologs, structural features, substrate specificities, and experimental strategies for studying DNA repair by AlkB family proteins.
Collapse
Affiliation(s)
- Bogdan I Fedeles
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Vipender Singh
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - James C Delaney
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Deyu Li
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
| | - John M Essigmann
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
| |
Collapse
|
25
|
Bellow JA, Yousif M, Fang D, Kratz EG, Cisneros GA, Groysman S. Synthesis and Reactions of 3d Metal Complexes with the Bulky Alkoxide Ligand [OCtBu2Ph]. Inorg Chem 2015; 54:5624-33. [DOI: 10.1021/acs.inorgchem.5b00795] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- James A. Bellow
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Maryam Yousif
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Dong Fang
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Eric G. Kratz
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - G. Andrés Cisneros
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Stanislav Groysman
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| |
Collapse
|
26
|
Verma P, Vogiatzis KD, Planas N, Borycz J, Xiao DJ, Long JR, Gagliardi L, Truhlar DG. Mechanism of Oxidation of Ethane to Ethanol at Iron(IV)-Oxo Sites in Magnesium-Diluted Fe2(dobdc). J Am Chem Soc 2015; 137:5770-81. [PMID: 25882096 DOI: 10.1021/jacs.5b00382] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The catalytic properties of the metal-organic framework Fe2(dobdc), containing open Fe(II) sites, include hydroxylation of phenol by pure Fe2(dobdc) and hydroxylation of ethane by its magnesium-diluted analogue, Fe0.1Mg1.9(dobdc). In earlier work, the latter reaction was proposed to occur through a redox mechanism involving the generation of an iron(IV)-oxo species, which is an intermediate that is also observed or postulated (depending on the case) in some heme and nonheme enzymes and their model complexes. In the present work, we present a detailed mechanism by which the catalytic material, Fe0.1Mg1.9(dobdc), activates the strong C-H bonds of ethane. Kohn-Sham density functional and multireference wave function calculations have been performed to characterize the electronic structure of key species. We show that the catalytic nonheme-Fe hydroxylation of the strong C-H bond of ethane proceeds by a quintet single-state σ-attack pathway after the formation of highly reactive iron-oxo intermediate. The mechanistic pathway involves three key transition states, with the highest activation barrier for the transfer of oxygen from N2O to the Fe(II) center. The uncatalyzed reaction, where nitrous oxide directly oxidizes ethane to ethanol is found to have an activation barrier of 280 kJ/mol, in contrast to 82 kJ/mol for the slowest step in the iron(IV)-oxo catalytic mechanism. The energetics of the C-H bond activation steps of ethane and methane are also compared. Dehydrogenation and dissociation pathways that can compete with the formation of ethanol were shown to involve higher barriers than the hydroxylation pathway.
Collapse
Affiliation(s)
- Pragya Verma
- †Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Konstantinos D Vogiatzis
- †Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Nora Planas
- †Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States.,⊥Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Joshua Borycz
- †Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Dianne J Xiao
- ‡Department of Chemistry, University of California, Berkeley, California 94720, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jeffrey R Long
- ‡Department of Chemistry, University of California, Berkeley, California 94720, United States.,§Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Laura Gagliardi
- †Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Donald G Truhlar
- †Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States.,∥Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
27
|
Lu X, Zhao BS, He C. TET family proteins: oxidation activity, interacting molecules, and functions in diseases. Chem Rev 2015; 115:2225-39. [PMID: 25675246 DOI: 10.1021/cr500470n] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Xingyu Lu
- †Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States.,‡Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Boxuan Simen Zhao
- †Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States.,‡Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Chuan He
- †Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States.,‡Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| |
Collapse
|