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Gu Y, Fan C, Yang H, Sun H, Wang X, Qiu X, Chen B, Li CM, Guo C. Fluorogenic RNA Aptamer-Based Amplification and Transcription Strategy for Label-free Sensing of Methyltransferase Activity in Complex Matrixes. Adv Biol (Weinh) 2024; 8:e2300668. [PMID: 38327153 DOI: 10.1002/adbi.202300668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Indexed: 02/09/2024]
Abstract
DNA methyltransferase is significant in cellular activities and gene expression, and its aberrant expression is closely linked to various cancers during initiation and progression. Currently, there is a great demand for reliable and label-free techniques for DNA methyltransferase evaluation in tumor diagnosis and cancer therapy. Herein, a low-background fluorescent RNA aptamer-based sensing approach for label-free quantification of cytosine-guanine (CpG) dinucleotides methyltransferase (M.SssI) is reported. The fluorogenic light-up RNA aptamers-based strategy exhibits high selectivity via restriction endonuclease, padlock-based recognition, and RNA transcription. By combining rolling circle amplification (RCA), and RNA transcription with fluorescence response of RNA aptamers of Spinach-dye compound, the proposed platform exhibited efficiently ultrahigh sensitivity toward M.SssI. Eventually, the detection can be achieved in a linear range of 0.02-100 U mL-1 with a detection limit of 1.6 × 10-3 U mL-1. Owing to these superior features, the method is further applied in serum samples spiked M.SssI, which delivers a recovery ranging from 92.0 to 107.0% and a relative standard deviation <7.0%, providing a promising and practical tool for determining M.SssI in complex biological matrices.
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Affiliation(s)
- Yu Gu
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
| | - Cunxia Fan
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
| | - Hongbin Yang
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
| | - Huiping Sun
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
| | - Xiaobao Wang
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
| | - Xingchen Qiu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
| | - Bo Chen
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
- Jiangsu Key Laboratory for Biomaterials and Devices, Department of Biological Science and Medical Engineering, Southeast University, Nanjing, 210009, P. R. China
| | - Chang-Ming Li
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
| | - Chunxian Guo
- Institute for Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Kerui Road, Suzhou, 215009, P.R. China
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Sun H, Zhou S, Liu Y, Lu P, Qi N, Wang G, Yang M, Huo D, Hou C. A fluorescent biosensor based on exponential amplification reaction-initiated CRISPR/Cas12a (EIC) strategy for ultrasensitive DNA methyltransferase detection. Anal Chim Acta 2023; 1239:340732. [PMID: 36628729 DOI: 10.1016/j.aca.2022.340732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/09/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
DNA methyltransferase (DNA MTase) catalyzes the process of DNA methylation, and the aberrant DNA MTase activity is closely associated with cancer incidence and progression. Inspired by the exponential amplification reaction (EXPAR) characteristics, we developed an EXPAR-initiated CRISPR/Cas12a (EIC) strategy for sensitively detecting DNA MTase activity. A hairpin probe (HP) was designed with a palindromic sequence in the stem as substrate and NH2-modified 3' end to prevent nonspecific amplification. HP could be methylated by DNA adenine methyltransferase (Dam MTase) and then digested by DpnI to generate an oligonucleotide that can serve as an EXPAR primer. With the assistance of Nt.BstNBI nicking enzyme and Vent(exo-) polymerase, this primer bound to template and induced EXPAR. Interestingly, the product of Cycle 1 in EXPAR can function as primer to initiate Cycle 2. Both EXPAR products can further activate the collateral cleavage of CRISPR/Cas12a-crRNA, resulting in the fragmentation of fluorescence reporters and fluorescence recovery. Due to the highly efficient amplification (about 5 times signal-to-noise of SDA) and the robust trans-cleavage of CRISPR/Cas12a, the EIC system owned an extreme limit of detection (LOD) of 2 × 10-4 U/mL and a broad detection range from 2 × 10-4 to 10 U/mL for Dam MTase. In addition, this method has succeeded in inhibitor screening and evaluation, showing magnificent promise in drug discovery and cancer therapy.
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Affiliation(s)
- Human Sun
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China.
| | - Shiying Zhou
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Yin Liu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Peng Lu
- Chongqing University Three Gorges Hospital, Chongqing, 404000, PR China
| | - Na Qi
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Guixue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Mei Yang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China.
| | - Danqun Huo
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China; Chongqing Key Laboratory of Bio-perception & Intelligent Information Processing, School of Microelectronics and Communication Engineering, Chongqing University, Chongqing, 400044, PR China.
| | - Changjun Hou
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China; National Facility for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, PR China.
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3
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Wang LJ, Han X, Qiu JG, Jiang B, Zhang CY. Cytosine-5 methylation-directed construction of a Au nanoparticle-based nanosensor for simultaneous detection of multiple DNA methyltransferases at the single-molecule level. Chem Sci 2020; 11:9675-9684. [PMID: 34094232 PMCID: PMC8161687 DOI: 10.1039/d0sc03240a] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/25/2020] [Indexed: 12/28/2022] Open
Abstract
DNA methylation at cytosine/guanine dinucleotide islands (CpGIs) is the most prominent epigenetic modification in prokaryotic and eukaryotic genomes. DNA methyltransferases (MTases) are responsible for genomic methylation, and their aberrant activities are closely associated with various diseases including cancers. However, the specific and sensitive detection of multiple DNA MTases has remained a great challenge due to the specificity of the methylase substrate and the rareness of methylation-sensitive restriction endonuclease species. Here, we demonstrate for the first time the cytosine-5 methylation-directed construction of a Au nanoparticle (AuNP)-based nanosensor for simultaneous detection of multiple DNA MTases at the single-molecule level. We used the methyl-directed endonuclease GlaI to cleave the site-specific 5-methylcytosine (5-mC). In the presence of CpG and GpC MTases (i.e., M.SssI and M.CviPI), their hairpin substrates are methylated at cytosine-5 to form the catalytic substrates for GlaI, respectively, followed by simultaneous cleavage by GlaI to yield two capture probes. These two capture probes can hybridize with the Cy5/Cy3-signal probes which are assembled on the AuNPs, respectively, to form the double-stranded DNAs (dsDNAs). Each dsDNA with a guanine ribonucleotide can act as the catalytic substrate for ribonuclease (RNase HII), inducing recycling cleavage of signal probes to liberate large numbers of Cy5 and Cy3 molecules from the AuNPs. The released Cy5 and Cy3 molecules can be simply quantified by total internal reflection fluorescence (TIRF)-based single-molecule imaging for simultaneous measurement of M.SssI and M.CviPI MTase activities. This method exhibits good specificity and high sensitivity with a detection limit of 2.01 × 10-3 U mL-1 for M.SssI MTase and 3.39 × 10-3 U mL-1 for M.CviPI MTase, and it can be further applied for discriminating different kinds of DNA MTases, screening potential inhibitors, and measuring DNA MTase activities in human serum and cell lysate samples, holding great potential in biomedical research, clinical diagnosis, drug discovery and cancer therapeutics.
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Affiliation(s)
- Li-Juan Wang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 China
| | - Xiao Han
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 China
| | - Jian-Ge Qiu
- Academy of Medical Sciences, Zhengzhou University Zhengzhou 450000 China
| | - BingHua Jiang
- Academy of Medical Sciences, Zhengzhou University Zhengzhou 450000 China
| | - Chun-Yang Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 China
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Meng L, Xiao K, Zhang X, Du C, Chen J. A novel signal-off photoelectrochemical biosensor for M.SssI MTase activity assay based on GQDs@ZIF-8 polyhedra as signal quencher. Biosens Bioelectron 2020; 150:111861. [DOI: 10.1016/j.bios.2019.111861] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 01/16/2023]
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5
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Du YC, Wang SY, Li XY, Wang YX, Tang AN, Kong DM. Terminal deoxynucleotidyl transferase-activated nicking enzyme amplification reaction for specific and sensitive detection of DNA methyltransferase and polynucleotide kinase. Biosens Bioelectron 2019; 145:111700. [DOI: 10.1016/j.bios.2019.111700] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/28/2019] [Accepted: 09/11/2019] [Indexed: 12/19/2022]
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6
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Xu X, Wang L, Li X, Cui W, Jiang W. Multiple sealed primers-mediated rolling circle amplification strategy for sensitive and specific detection of DNA methyltransferase activity. Talanta 2018; 194:282-288. [PMID: 30609532 DOI: 10.1016/j.talanta.2018.09.113] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 09/20/2018] [Accepted: 09/30/2018] [Indexed: 01/19/2023]
Abstract
DNA methyltransferase (MTase) aberrant expression has a close relationship to tumorigenesis. DNA MTase activity detection is of great importance to its biomedical research and theranostics study. Here, multiple sealed primers-mediated rolling circle amplification (RCA) strategy is developed for sensitively and specifically detecting DNA MTase activity. The DNA probe has a folded, double-loop structure that seals multiple primers. First, in the presence of DNA MTase, the DNA probe is methylated, which then gets cleaved by the restriction endonuclease and breaks into multiple DNA oligonucleotide fragments. Second, each DNA oligonucleotide fragment acts as an independent primer for triggering RCA reaction respectively, producing long DNA strands that contain several interval G-quadruplexes. Finally, copious of G-quadruplexes are obtained, which bind N-methylmesoporphyrin IX (NMM) to generate significantly enhanced fluorescence. When DNA MTase is absent or inactive, the DNA probe is stable and cannot release the primers for RCA reaction. In the proposed strategy, the action of DNA MTase on one DNA probe is converted to the multiple amplifications triggered by multiple released primers. The detection limit for Dam MTase is down to 0.0085 U/mL, and the target MTase can be well discriminated from its MTases analogues. The method is utilized in screening of Dam MTase inhibitors and analyzing of spiked Dam MTase in biological samples. The results suggest that the strategy may provide a promising tool for DNA MTase activity detection in biomedical research and cancer theranostics.
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Affiliation(s)
- Xiaowen Xu
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China
| | - Lei Wang
- School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China
| | - Xia Li
- Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China
| | - Wanling Cui
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China
| | - Wei Jiang
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China.
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7
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Zhang Y, Wang XY, Zhang Q, Zhang CY. Label-Free Sensitive Detection of DNA Methyltransferase by Target-Induced Hyperbranched Amplification with Zero Background Signal. Anal Chem 2017; 89:12408-12415. [PMID: 29083155 DOI: 10.1021/acs.analchem.7b03490] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
DNA methyltransferases (MTases) may specifically recognize the short palindromic sequences and transfer a methyl group from S-adenosyl-l-methionine to target cytosine/adenine. The aberrant DNA methylation is linked to the abnormal DNA MTase activity, and some DNA MTases have become promising targets of anticancer/antimicrobial drugs. However, the reported DNA MTase assays often involve laborious operation, expensive instruments, and radio-labeled substrates. Here, we develop a simple and label-free fluorescent method to sensitively detect DNA adenine methyltransferase (Dam) on the basis of terminal deoxynucleotidyl transferase (TdT)-activated Endonuclease IV (Endo IV)-assisted hyperbranched amplification. We design a hairpin probe with a palindromic sequence in the stem as the substrate and a NH2-modified 3' end for the prevention of nonspecific amplification. The substrate may be methylated by Dam and subsequently cleaved by DpnI, producing three single-stranded DNAs, two of which with 3'-OH termini may be amplified by hyperbranched amplification to generate a distinct fluorescence signal. Because high exactitude of TdT enables the amplification only in the presence of free 3'-OH termini and Endo IV only hydrolyzes the intact apurinic/apyrimidinic sites in double-stranded DNAs, zero background signal can be achieved. This method exhibits excellent selectivity and high sensitivity with a limit of detection of 0.003 U/mL for pure Dam and 9.61 × 10-6 mg/mL for Dam in E. coli cells. Moreover, it can be used to screen the Dam inhibitors, holding great potentials in disease diagnosis and drug development.
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Affiliation(s)
- Yan Zhang
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University , Jinan 250014, China
| | - Xin-Yan Wang
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University , Jinan 250014, China
| | - Qianyi Zhang
- Nantou High School Shenzhen , Shenzhen, 518052, China
| | - Chun-Yang Zhang
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University , Jinan 250014, China
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8
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Assay of DNA methyltransferase 1 activity based on uracil-specific excision reagent digestion induced G-quadruplex formation. Anal Chim Acta 2017; 986:131-137. [DOI: 10.1016/j.aca.2017.07.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/05/2017] [Accepted: 07/11/2017] [Indexed: 12/23/2022]
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9
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A label-free electrochemical biosensor for methyltransferase activity detection and inhibitor screening based on graphene quantum dot and enzyme-catalyzed reaction. J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2017.06.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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10
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Ma C, Liu H, Li W, Chen H, Jin S, Wang J, Wang J. Label-free monitoring of DNA methyltransferase activity based on terminal deoxynucleotidyl transferase using a thioflavin T probe. Mol Cell Probes 2016; 30:118-21. [DOI: 10.1016/j.mcp.2016.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 01/09/2016] [Accepted: 02/02/2016] [Indexed: 01/17/2023]
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Jin S, Liu H, Xia K, Ma C, He H, Wang K. Real-time monitoring of DNA methyltransferase activity using a hemimethylated smart probe. Mol Cell Probes 2016; 30:185-7. [PMID: 27039360 DOI: 10.1016/j.mcp.2016.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 03/15/2016] [Accepted: 03/29/2016] [Indexed: 01/20/2023]
Abstract
A real-time assay for DNA methyltransferase (MTase) activity has been developed. A hemimethylated smart probe is used as the substrate for DNA MTase. Cleavage of the methylated product leads to separation of fluorophore from quencher, giving a proportional increase in fluorescence. The method permits real-time monitoring of DNA methylation process and makes it easy to characterize the activity of DNA MTase. It also has the potential to screen suitable inhibitor drugs for DNA MTase.
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Affiliation(s)
- Shunxin Jin
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Haisheng Liu
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Kun Xia
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Changbei Ma
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China; State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410081, China.
| | - Hailun He
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410081, China
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12
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Zhang Y, Xu WJ, Zeng YP, Zhang CY. Sensitive detection of DNA methyltransferase activity by transcription-mediated duplex-specific nuclease-assisted cyclic signal amplification. Chem Commun (Camb) 2015; 51:13968-71. [DOI: 10.1039/c5cc05922d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We develop transcription-mediated duplex-specific nuclease-assisted cyclic signal amplification for sensitive detection of DNA methyltransferase activity.
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Affiliation(s)
- Yan Zhang
- Single-Molecule Detection and Imaging Laboratory
- Key Lab of Health Informatics of Chinese Academy of Sciences
- Shenzhen Institutes of Advanced Technology
- Chinese Academy of Sciences
- Shenzhen 518055
| | - Wen-jing Xu
- Single-Molecule Detection and Imaging Laboratory
- Key Lab of Health Informatics of Chinese Academy of Sciences
- Shenzhen Institutes of Advanced Technology
- Chinese Academy of Sciences
- Shenzhen 518055
| | - Ya-ping Zeng
- Single-Molecule Detection and Imaging Laboratory
- Key Lab of Health Informatics of Chinese Academy of Sciences
- Shenzhen Institutes of Advanced Technology
- Chinese Academy of Sciences
- Shenzhen 518055
| | - Chun-yang Zhang
- Single-Molecule Detection and Imaging Laboratory
- Key Lab of Health Informatics of Chinese Academy of Sciences
- Shenzhen Institutes of Advanced Technology
- Chinese Academy of Sciences
- Shenzhen 518055
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Tian T, Xiao H, Long Y, Zhang X, Wang S, Zhou X, Liu S, Zhou X. Sensitive analysis of DNA methyltransferase based on a hairpin-shaped DNAzyme. Chem Commun (Camb) 2012; 48:10031-3. [DOI: 10.1039/c2cc35648a] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Sheflyan GY, Kubareva EA, Gromova ES. Methods for the covalent attachment of nucleic acids and their derivatives to proteins. RUSSIAN CHEMICAL REVIEWS 2007. [DOI: 10.1070/rc1996v065n08abeh000277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Evdokimov AA, Sclavi B, Zinoviev VV, Malygin EG, Hattman S, Buckle M. Study of Bacteriophage T4-encoded Dam DNA (Adenine-N6)-methyltransferase Binding with Substrates by Rapid Laser UV Cross-linking. J Biol Chem 2007; 282:26067-76. [PMID: 17630395 DOI: 10.1074/jbc.m700866200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA methyltransferases of the Dam family (including bacteriophage T4-encoded Dam DNA (adenine-N(6))-methyltransferase (T4Dam)) catalyze methyl group transfer from S-adenosyl-L-methionine (AdoMet), producing S-adenosyl-L-homocysteine (AdoHcy) and methylated adenine residues in palindromic GATC sequences. In this study, we describe the application of direct (i.e. no exogenous cross-linking reagents) laser UV cross-linking as a universal non-perturbing approach for studying the characteristics of T4Dam binding with substrates in the equilibrium and transient modes of interaction. UV irradiation of the enzyme.substrate complexes using an Nd(3+):yttrium aluminum garnet laser at 266 nm resulted in up to 3 and >15% yields of direct T4Dam cross-linking to DNA and AdoMet, respectively. Consequently, we were able to measure equilibrium constants and dissociation rates for enzyme.substrate complexes. In particular, we demonstrate that both reaction substrates, specific DNA and AdoMet (or product AdoHcy), stabilized the ternary complex. The improved substrate affinity for the enzyme in the ternary complex significantly reduced dissociation rates (up to 2 orders of magnitude). Several of the parameters obtained (such as dissociation rate constants for the binary T4Dam.AdoMet complex and for enzyme complexes with a nonfluorescent hemimethylated DNA duplex) were previously inaccessible by other means. However, where possible, the results of laser UV cross-linking were compared with those of fluorescence analysis. Our study suggests that rapid laser UV cross-linking efficiently complements standard DNA methyltransferase-related tools and is a method of choice to probe enzyme-substrate interactions in cases in which data cannot be acquired by other means.
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Affiliation(s)
- Alexey A Evdokimov
- Federal State Research Institute State Research Center of Virology and Biotechnology Vector, Novosibirsk 630559, Russia
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16
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Liebert K, Horton JR, Chahar S, Orwick M, Cheng X, Jeltsch A. Two alternative conformations of S-adenosyl-L-homocysteine bound to Escherichia coli DNA adenine methyltransferase and the implication of conformational changes in regulating the catalytic cycle. J Biol Chem 2007; 282:22848-55. [PMID: 17545164 DOI: 10.1074/jbc.m700926200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The crystal structure of the Escherichia coli DNA adenine methyltransferase (EcoDam) in a binary complex with the cofactor product S-adenosyl-L-homocysteine (AdoHcy) unexpectedly showed the bound AdoHcy in two alternative conformations, extended or folded. The extended conformation represents the catalytically competent conformation, identical to that of EcoDam-DNA-AdoHcy ternary complex. The folded conformation prevents catalysis, because the homocysteine moiety occupies the target Ade binding pocket. The largest difference between the binary and ternary structures is in the conformation of the N-terminal hexapeptide ((9)KWAGGK(14)). Cofactor binding leads to a strong change in the fluorescence of Trp(10), whose indole ring approaches the cofactor by 3.3A(.) Stopped-flow kinetics and AdoMet cross-linking studies indicate that the cofactor prefers binding to the enzyme after preincubation with DNA. In the presence of DNA, AdoMet binding is approximately 2-fold stronger than AdoHcy binding. In the binary complex the side chain of Lys(14) is disordered, whereas Lys(14) stabilizes the active site in the ternary complex. Fluorescence stopped-flow experiments indicate that Lys(14) is important for EcoDam binding of the extrahelical target base into the active site pocket. This suggests that the hexapeptide couples specific DNA binding (Lys(9)), AdoMet binding (Trp(10)), and insertion of the flipped target base into the active site pocket (Lys(14)).
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Affiliation(s)
- Kirsten Liebert
- Biochemistry Laboratory, School of Engineering and Science, Jacobs University Bremen, 28759 Bremen, Germany
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Abstract
Recognition of a specific DNA sequence by a protein is probably the best example of macromolecular interactions leading to various events. It is a prerequisite to understanding the basis of protein-DNA interactions to obtain a better insight into fundamental processes such as transcription, replication, repair, and recombination. DNA methyltransferases with varying sequence specificities provide an excellent model system for understanding the molecular mechanism of specific DNA recognition. Sequence comparison of cloned genes, along with mutational analyses and recent crystallographic studies, have clearly defined the functions of various conserved motifs. These enzymes access their target base in an elegant manner by flipping it out of the DNA double helix. The drastic protein-induced DNA distortion, first reported for HhaI DNA methyltransferase, appears to be a common mechanism employed by various proteins that need to act on bases. A remarkable feature of the catalytic mechanism of DNA (cytosine-5) methyltransferases is the ability of these enzymes to induce deamination of the target cytosine in the absence of S-adenosyl-L-methionine or its analogs. The enzyme-catalyzed deamination reaction is postulated to be the major cause of mutational hotspots at CpG islands responsible for various human genetic disorders. Methylation of adenine residues in Escherichia coli is known to regulate various processes such as transcription, replication, repair, recombination, transposition, and phage packaging.
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Affiliation(s)
- I Ahmad
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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Ying Z, Janney N, Houtz RL. Organization and characterization of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit epsilon N-methyltransferase gene in tobacco. PLANT MOLECULAR BIOLOGY 1996; 32:663-71. [PMID: 8980518 DOI: 10.1007/bf00020207] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/1996] [Accepted: 06/28/1996] [Indexed: 05/22/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit (LS) epsilon N-methyltransferase (Rubisco LSMT) catalyzes the posttranslational methylation of the epsilon-amino group of Lys-14 in the LS of Rubisco in many higher plant species including tobacco. The tobacco Rubisco LSMT gene (rbcMT-T) and its cDNA were isolated, sequenced, and characterized. The gene contains 6 exons and spans about 6 kb. Primer extension analysis indicated one transcription start site located 93 nt upstream of the translation initiation site. Sequence analysis of the 5'-flanking region suggests several potential binding sites for transcription factors, including 7 GT-1 elements and an HSP-70.5 element. Gene dosage analysis by Southern hybridization demonstrated that the tobacco rbcMT-T gene is present as a single copy in the tobacco haploid genome. The full-length cDNA for tobacco rbcMT-T is 1974 nt in length excluding the 3' poly(A)15 tail, and encodes a 491 amino acid polypeptide with a molecular mass of ca. 56kDa. The deduced amino acid sequence of tobacco Rubisco LSMT has 64.5% identity and 75.3% similarity with the sequence of pea Rubisco LSMT, and both proteins contain several copies of a conserved imperfect leucine-rich repeat motif.
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Affiliation(s)
- Z Ying
- Department of Horticulture and Landscape Architecture, University of Kentucky, Lexington 40546, USA
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Finta C, Sulima U, Venetianer P, Kiss A. Purification of the KpnI DNA methyltransferase and photolabeling of the enzyme with S-adenosyl-L-methionine. Gene 1995; 164:65-9. [PMID: 7590323 DOI: 10.1016/0378-1119(95)00439-d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An Escherichia coli strain overproducing the KpnI DNA methyltransferase (M.KpnI) was constructed by cloning the kpnIM gene downstream from the inducible T7 phage luminal diameter 10 promoter. A method involving three chromatographic steps has been developed to purify M.KpnI to homogeneity. The purified enzyme has a pH optimum around 7.3 and is inhibited by salts. M.KpnI can be photolabeled by UV-irradiation of the enzyme in the presence of S-adenosyl-L-[methyl-3H]methionine ([methyl-3H]AdoMet). Photolabeling results from a specific interaction between M.KpnI and AdoMet, as indicated by the dependence of photolabeling on native enzyme conformation and by the inhibitory effect of the AdoMet analogs, sinefungin and S-adenosyl-L-homocysteine (AdoHcy).
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Affiliation(s)
- C Finta
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
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