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Tao S, Run Y, Monchaud D, Zhang W. i-Motif DNA: identification, formation, and cellular functions. Trends Genet 2024:S0168-9525(24)00133-1. [PMID: 38902139 DOI: 10.1016/j.tig.2024.05.011] [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: 04/24/2024] [Revised: 05/29/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024]
Abstract
An i-motif (iM) is a four-stranded (quadruplex) DNA structure that folds from cytosine (C)-rich sequences. iMs can fold under many different conditions in vitro, which paves the way for their formation in living cells. iMs are thought to play key roles in various DNA transactions, notably in the regulation of genome stability, gene transcription, mRNA translation, DNA replication, telomere and centromere functions, and human diseases. We summarize the different techniques used to assess the folding of iMs in vitro and provide an overview of the internal and external factors that affect their formation and stability in vivo. We describe the possible biological relevance of iMs and propose directions towards their use as target in biology.
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Affiliation(s)
- Shentong Tao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China
| | - Yonghang Run
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China
| | - David Monchaud
- Institut de Chimie Moleculaire de l'Université de Bourgogne (ICMUB), Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6302, Université Bourgogne Franche Comté (UBFC), Dijon, France
| | - Wenli Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China.
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2
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Li KS, Jordan D, Lin LY, McCarthy SE, Schneekloth JS, Yatsunyk LA. Crystal Structure of an i-Motif from the HRAS Oncogene Promoter. Angew Chem Int Ed Engl 2023; 62:e202301666. [PMID: 36995904 PMCID: PMC10330059 DOI: 10.1002/anie.202301666] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023]
Abstract
An i-motif is a non-canonical DNA structure implicated in gene regulation and linked to cancers. The C-rich strand of the HRAS oncogene, 5'-CGCCCGTGCCCTGCGCCCGCAACCCGA-3' (herein referred to as iHRAS), forms an i-motif in vitro but its exact structure was unknown. HRAS is a member of the RAS proto-oncogene family. About 19 % of US cancer patients carry mutations in RAS genes. We solved the structure of iHRAS at 1.77 Å resolution. The structure reveals that iHRAS folds into a double hairpin. The two double hairpins associate in an antiparallel fashion, forming an i-motif dimer capped by two loops on each end and linked by a connecting region. Six C-C+ base pairs form each i-motif core, and the core regions are extended by a G-G base pair and a cytosine stacking. Extensive canonical and non-canonical base pairing and stacking stabilizes the connecting region and loops. The iHRAS structure is the first atomic resolution structure of an i-motif from a human oncogene. This structure sheds light on i-motifs folding and function in the cell.
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Affiliation(s)
- Kevin S Li
- Department Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Deondre Jordan
- Department Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Linda Y Lin
- Department Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Sawyer E McCarthy
- Department Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - John S Schneekloth
- Chemical Biology Laboratory, National Cancer Institute, National Institute of Health, Frederick, MD 21702, USA
| | - Liliya A Yatsunyk
- Department Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
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3
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Wang W, Shen Y, Wei B. Controllable dynamics of complex DNA nanostructures. NANOSCALE 2023; 15:4795-4800. [PMID: 36806876 DOI: 10.1039/d2nr05872c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In the past four decades, a variety of self-assembly design frameworks have led to the construction of versatile DNA nanostructures with increasing complexity and controllability. The controllable dynamics of DNA nanostructures has garnered much interest and emerged as a powerful tool for conducting sophisticated tasks at the molecular level. In this minireview, we summarized the controllable reconfigurations of complex DNA nanostructures induced by nucleic acid strands, environmental stimuli and enzymatic treatments. We also envisioned that with the optimization of response time, sensitivity and specificity, dynamic DNA nanostructures have great promise in applications ranging from nanorobotics to life sciences.
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Affiliation(s)
- Wen Wang
- BGI Research, BGI, Shenzhen 518083, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, Shenzhen 518120, China.
| | - Yue Shen
- BGI Research, BGI, Shenzhen 518083, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, Shenzhen 518120, China.
| | - Bryan Wei
- School of Life Sciences, Tsinghua University-Peking University Center for Life Sciences, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China.
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4
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Yang T, Xu Q, Chen J, Jia PK, Xie BB, Wang D, Zhou X, Shao Y. Selectively Identifying Exposed-over-Unexposed C-C + Pairs in Human Telomeric i-Motif Structures with Length-Dependent Polymorphism. Anal Chem 2022; 94:14994-15001. [PMID: 36263663 DOI: 10.1021/acs.analchem.2c02875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The i-motif structure (iM) has attracted much attention, because of its in vivo bioactivity and wide in vitro applications such as DNA-based switches. Herein, the length-dependent folding of cytosine-rich repeats of the human telomeric 5'-(CCCTAA)n-1CCC-3' (iM-n, where n = 2-8) was fully explored. We found that iM-4, iM-5, and iM-8 mainly form the intramolecular monomer iM structures, while a tetramolecular structure populates only for iM-3. However, iM-6 and iM-7 have the potential to fold as well into the dimeric iM structures besides the monomer ones. The natural hypericin (Hyp) was used as the polymorphism-selective probe to recognize the iM structures. Interestingly, only iM-3, iM-6, and iM-7 can efficiently switch on the Hyp fluorescence by specifically binding with the outmost C-C+ base pairs that are exposed directly to solution. However, other iM structures that fold in a way with a coverage of the outmost C-C+ pairs by loop sequences are totally unavailable for the Hyp binding. Theoretical modeling indicates that adaptive π-π and cation-π interactions contribute to the Hyp recognition toward the exposed C-C+ pairs. This specific iM recognition can be boosted by a photocatalytic DNAzyme construct. Our work provides a reliable fluorescence method to selectively explore the polymorphism of iM structures.
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Affiliation(s)
- Tong Yang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Qiuda Xu
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Jiahui Chen
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Pei-Ke Jia
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, People's Republic of China
| | - Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, People's Republic of China
| | - Dandan Wang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Xiaoshun Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Yong Shao
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
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5
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Mendes E, Aljnadi IM, Bahls B, Victor BL, Paulo A. Major Achievements in the Design of Quadruplex-Interactive Small Molecules. Pharmaceuticals (Basel) 2022; 15:300. [PMID: 35337098 PMCID: PMC8953082 DOI: 10.3390/ph15030300] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/17/2022] Open
Abstract
Organic small molecules that can recognize and bind to G-quadruplex and i-Motif nucleic acids have great potential as selective drugs or as tools in drug target discovery programs, or even in the development of nanodevices for medical diagnosis. Hundreds of quadruplex-interactive small molecules have been reported, and the challenges in their design vary with the intended application. Herein, we survey the major achievements on the therapeutic potential of such quadruplex ligands, their mode of binding, effects upon interaction with quadruplexes, and consider the opportunities and challenges for their exploitation in drug discovery.
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Affiliation(s)
- Eduarda Mendes
- Faculty of Pharmacy, Research Institute for Medicines (iMed.Ulisboa), Universidade de Lisboa, 1649-003 Lisbon, Portugal; (E.M.); (I.M.A.); (B.B.)
| | - Israa M. Aljnadi
- Faculty of Pharmacy, Research Institute for Medicines (iMed.Ulisboa), Universidade de Lisboa, 1649-003 Lisbon, Portugal; (E.M.); (I.M.A.); (B.B.)
- Faculty of Sciences, BioISI, Biosystems and Integrative Sciences Institute, Universidade de Lisboa, 1749-016 Lisbon, Portugal;
| | - Bárbara Bahls
- Faculty of Pharmacy, Research Institute for Medicines (iMed.Ulisboa), Universidade de Lisboa, 1649-003 Lisbon, Portugal; (E.M.); (I.M.A.); (B.B.)
- Faculty of Sciences, BioISI, Biosystems and Integrative Sciences Institute, Universidade de Lisboa, 1749-016 Lisbon, Portugal;
| | - Bruno L. Victor
- Faculty of Sciences, BioISI, Biosystems and Integrative Sciences Institute, Universidade de Lisboa, 1749-016 Lisbon, Portugal;
| | - Alexandra Paulo
- Faculty of Pharmacy, Research Institute for Medicines (iMed.Ulisboa), Universidade de Lisboa, 1649-003 Lisbon, Portugal; (E.M.); (I.M.A.); (B.B.)
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6
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Wang W, Chen C, Vecchioni S, Zhang T, Wu C, Ohayon YP, Sha R, Seeman NC, Wei B. Reconfigurable Two‐Dimensional DNA Lattices: Static and Dynamic Angle Control. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202112487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wen Wang
- School of Life Sciences Tsinghua University-Peking University Center for Life Sciences Center for Synthetic and Systems Biology Tsinghua University Beijing 100084 China
| | - Chunyu Chen
- School of Life Sciences Tsinghua University-Peking University Center for Life Sciences Center for Synthetic and Systems Biology Tsinghua University Beijing 100084 China
| | - Simon Vecchioni
- Department of Chemistry New York University New York New York 10003 USA
| | - Tianqing Zhang
- School of Life Sciences Tsinghua University-Peking University Center for Life Sciences Center for Synthetic and Systems Biology Tsinghua University Beijing 100084 China
| | - Chengxian Wu
- School of Life Sciences Tsinghua University-Peking University Center for Life Sciences Center for Synthetic and Systems Biology Tsinghua University Beijing 100084 China
| | - Yoel P. Ohayon
- Department of Chemistry New York University New York New York 10003 USA
| | - Ruojie Sha
- Department of Chemistry New York University New York New York 10003 USA
| | - Nadrian C. Seeman
- Department of Chemistry New York University New York New York 10003 USA
| | - Bryan Wei
- School of Life Sciences Tsinghua University-Peking University Center for Life Sciences Center for Synthetic and Systems Biology Tsinghua University Beijing 100084 China
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7
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Wang W, Chen C, Vecchioni S, Zhang T, Wu C, Ohayon YP, Sha R, Seeman NC, Wei B. Reconfigurable Two-Dimensional DNA Lattices: Static and Dynamic Angle Control. Angew Chem Int Ed Engl 2021; 60:25781-25786. [PMID: 34596325 DOI: 10.1002/anie.202112487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Indexed: 11/11/2022]
Abstract
Branched DNA motifs serve as the basic construction elements for all synthetic DNA nanostructures. However, precise control of branching orientation remains a key challenge to further heighten the overall structural order. In this study, we use two strategies to control the branching orientation. The first one is based on immobile Holliday junctions which employ specific nucleotide sequences at the branch points which dictate their orientation. The second strategy is to use angle-enforcing struts to fix the branching orientation with flexible spacers at the branch points. We have also demonstrated that the branching orientation control can be achieved dynamically, either by canonical Watson-Crick base pairing or non-canonical nucleobase interactions (e.g., i-motif and G-quadruplex). With precise angle control and feedback from the chemical environment, these results will enable novel DNA nanomechanical sensing devices, and precisely-ordered three-dimensional architectures.
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Affiliation(s)
- Wen Wang
- School of Life Sciences, Tsinghua University-Peking University Center for Life Sciences, Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Chunyu Chen
- School of Life Sciences, Tsinghua University-Peking University Center for Life Sciences, Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Simon Vecchioni
- Department of Chemistry, New York University, New York, New York, 10003, USA
| | - Tianqing Zhang
- School of Life Sciences, Tsinghua University-Peking University Center for Life Sciences, Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Chengxian Wu
- School of Life Sciences, Tsinghua University-Peking University Center for Life Sciences, Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Yoel P Ohayon
- Department of Chemistry, New York University, New York, New York, 10003, USA
| | - Ruojie Sha
- Department of Chemistry, New York University, New York, New York, 10003, USA
| | - Nadrian C Seeman
- Department of Chemistry, New York University, New York, New York, 10003, USA
| | - Bryan Wei
- School of Life Sciences, Tsinghua University-Peking University Center for Life Sciences, Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
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8
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Chaudhuri R, Fatma K, Dash J. Regulation of gene expression by targeting DNA secondary structures. J CHEM SCI 2021. [DOI: 10.1007/s12039-021-01898-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Cheng M, Chen J, Ju H, Zhou J, Mergny JL. Drivers of i-DNA Formation in a Variety of Environments Revealed by Four-Dimensional UV Melting and Annealing. J Am Chem Soc 2021; 143:7792-7807. [PMID: 33988990 DOI: 10.1021/jacs.1c02209] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
i-DNA is a four-stranded, pH-sensitive structure formed by cytosine-rich DNA sequences. Previous reports have addressed the conditions for formation of this motif in DNA in vitro and validated its existence in human cells. Unfortunately, these in vitro studies have often been performed under different experimental conditions, making comparisons difficult. To overcome this, we developed a four-dimensional UV melting and annealing (4DUVMA) approach to analyze i-DNA formation under a variety of conditions (e.g., pH, temperature, salt, crowding). Analysis of 25 sequences provided a global understanding of i-DNA formation under disparate conditions, which should ultimately allow the design of accurate prediction tools. For example, we found reliable linear correlations between the midpoint of pH transition and temperature (-0.04 ± 0.003 pH unit per 1.0 °C temperature increment) and between the melting temperature and pH (-23.8 ± 1.1 °C per pH unit increment). In addition, by analyzing the hysteresis between denaturing and renaturing profiles in both pH and thermal transitions, we found that loop length, nature of the C-tracts, pH, temperature, and crowding agents all play roles in i-DNA folding kinetics. Interestingly, our data indicate which conformer is more favorable for the sequences with an odd number of cytosine base pairs. Then the thermal and pH stabilities of "native" i-DNAs from human promoter genes were measured under near physiological conditions (pH 7.0, 37 °C). The 4DUVMA method can become a universal resource to analyze the properties of any i-DNA-prone sequence.
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Affiliation(s)
- Mingpan Cheng
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China.,ARNA Laboratory, Université de Bordeaux, INSERM U1212, CNRS UMR5320, IECB, Pessac 33607, France
| | - Jielin Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Huangxian Ju
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jun Zhou
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jean-Louis Mergny
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China.,ARNA Laboratory, Université de Bordeaux, INSERM U1212, CNRS UMR5320, IECB, Pessac 33607, France.,Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, Palaiseau Cedex 91128, France
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10
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Abstract
DNA has played an early and powerful role in the development of bottom-up nanotechnologies, not least because of DNA's precise, predictable, and controllable properties of assembly on the nanometer scale. Watson-Crick complementarity has been used to build complex 2D and 3D architectures and design a number of nanometer-scale systems for molecular computing, transport, motors, and biosensing applications. Most of such devices are built with classical B-DNA helices and involve classical A-T/U and G-C base pairs. However, in addition to the above components underlying the iconic double helix, a number of alternative pairing schemes of nucleobases are known. This review focuses on two of these noncanonical classes of DNA helices: G-quadruplexes and the i-motif. The unique properties of these two classes of DNA helix have been utilized toward some remarkable constructions and applications: G-wires; nanostructures such as DNA origami; reconfigurable structures and nanodevices; the formation and utilization of hemin-utilizing DNAzymes, capable of generating varied outputs from biosensing nanostructures; composite nanostructures made up of DNA as well as inorganic materials; and the construction of nanocarriers that show promise for the therapeutics of diseases.
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Affiliation(s)
- Jean-Louis Mergny
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering , Nanjing University , Nanjing 210023 , China.,ARNA Laboratory , Université de Bordeaux, Inserm U 1212, CNRS UMR5320, IECB , Pessac 33600 , France.,Institute of Biophysics of the CAS , v.v.i., Královopolská 135 , 612 65 Brno , Czech Republic
| | - Dipankar Sen
- Department of Molecular Biology & Biochemistry , Simon Fraser University , Burnaby , British Columbia V5A 1S6 , Canada.,Department of Chemistry , Simon Fraser University , Burnaby , British Columbia V5A 1S6 , Canada
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Zhou Z, Liu X, Yue L, Willner I. Controlling the Catalytic and Optical Properties of Aggregated Nanoparticles or Semiconductor Quantum Dots Using DNA-Based Constitutional Dynamic Networks. ACS NANO 2018; 12:10725-10735. [PMID: 30256615 DOI: 10.1021/acsnano.8b05452] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nucleic acid-based constitutional dynamic networks (CDNs) attract growing interest as a means to mimic complex biological networks. The triggered stabilization of the CDNs allows the dictated guided reversible reconfiguration and re-equilibration of the CDNs to other CDN configurations, where some of the constituents are up-regulated, while other constituents are down-regulated. Although substantial progress in controlling the adaptive dynamic control of the compositions of networks by means of auxiliary triggers was demonstrated, the use of CDNs as active ensembles for controlling chemical functionalities is still a challenge. We report on the assembly of signal-triggered CDN systems that guide the switchable aggregation of Au nanoparticles (NPs), thereby controlling their plasmonic properties and their catalytic functions (Au NPs-catalyzed oxidation of l-DOPA to dopachrome). In addition, we demonstrate that the triggered and orthogonal up-regulation and down-regulation of the constituents of the CDNs leads to the dictated aggregation of different-sized CdSe/ZnS quantum dots (QDs), cross-linked by K+-ion-stabilized G-quadruplex units. The incorporation of hemin into the G-quadruplex cross-linking units yields horseradish peroxidase-mimicking DNAzyme units that catalyze the generation of chemiluminescence via the oxidation of luminol by H2O2. The resulting chemiluminescence stimulates the chemiluminescence resonance energy transfer (CRET) process to the QDs, resulting in the luminescence of the two-sized QDs. By the application of appropriate triggers, the CDN-dictated up-regulation and down-regulation of the different-sized QDs aggregates are demonstrated, and the control over the photophysical functions of the different-sized QDs, by means of the CDNs, is highlighted.
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Affiliation(s)
- Zhixin Zhou
- Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
| | - Xia Liu
- Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
| | - Liang Yue
- Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
| | - Itamar Willner
- Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
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12
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Wang S, Yue L, Li Z, Zhang J, Tian H, Willner I. Light‐Induced Reversible Reconfiguration of DNA‐Based Constitutional Dynamic Networks: Application to Switchable Catalysis. Angew Chem Int Ed Engl 2018; 57:8105-8109. [DOI: 10.1002/anie.201803371] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Shan Wang
- Institute of ChemistryThe Center for Nanoscience and NanotechnologyThe Hebrew University of Jerusalem Jerusalem 91904 Israel
| | - Liang Yue
- Institute of ChemistryThe Center for Nanoscience and NanotechnologyThe Hebrew University of Jerusalem Jerusalem 91904 Israel
| | - Zi‐Yuan Li
- Key Laboratory for Advanced MaterialsSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology Shanghai China
| | - Junji Zhang
- Key Laboratory for Advanced MaterialsSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology Shanghai China
| | - He Tian
- Key Laboratory for Advanced MaterialsSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology Shanghai China
| | - Itamar Willner
- Institute of ChemistryThe Center for Nanoscience and NanotechnologyThe Hebrew University of Jerusalem Jerusalem 91904 Israel
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13
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Wang S, Yue L, Li Z, Zhang J, Tian H, Willner I. Light‐Induced Reversible Reconfiguration of DNA‐Based Constitutional Dynamic Networks: Application to Switchable Catalysis. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803371] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Shan Wang
- Institute of ChemistryThe Center for Nanoscience and NanotechnologyThe Hebrew University of Jerusalem Jerusalem 91904 Israel
| | - Liang Yue
- Institute of ChemistryThe Center for Nanoscience and NanotechnologyThe Hebrew University of Jerusalem Jerusalem 91904 Israel
| | - Zi‐Yuan Li
- Key Laboratory for Advanced MaterialsSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology Shanghai China
| | - Junji Zhang
- Key Laboratory for Advanced MaterialsSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology Shanghai China
| | - He Tian
- Key Laboratory for Advanced MaterialsSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology Shanghai China
| | - Itamar Willner
- Institute of ChemistryThe Center for Nanoscience and NanotechnologyThe Hebrew University of Jerusalem Jerusalem 91904 Israel
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14
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Yue L, Wang S, Lilienthal S, Wulf V, Remacle F, Levine RD, Willner I. Intercommunication of DNA-Based Constitutional Dynamic Networks. J Am Chem Soc 2018; 140:8721-8731. [DOI: 10.1021/jacs.8b03450] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Liang Yue
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Shan Wang
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Sivan Lilienthal
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Verena Wulf
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Françoise Remacle
- Department of Chemistry, University of Liege, B6c, 4000 Liege, Belgium
| | - R. D. Levine
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Itamar Willner
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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15
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Ishida R, Iwahashi H. Detection of protonated non-Watson-Crick base pairs using electrospray ionization mass spectrometry. J Biochem 2018; 163:215-222. [PMID: 29087477 DOI: 10.1093/jb/mvx073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/11/2017] [Indexed: 11/13/2022] Open
Abstract
Many studies have shown that protonated nucleic acid base pairs are involved in a wide variety of nucleic acid structures. However, little information is available on relative stability of hemiprotonated self- and non-self-dimers at monomer level. We used electrospray ionization mass spectrometry (ESI-MS) to evaluate the relative stability under various concentrations of hydrogen ion. These enable conjecture of the formation of protonated non-Watson-Crick base pairs based on DNA and RNA base sequence. In the present study, we observed that ESI-MS peaks corresponded to respective self-dimers for all examined nucleosides except for adenosine. Peak heights depended on the concentration of hydrogen ion. The ESI-MS peak heights of the hemiprotonated cytidine dimers and the hemiprotonated thymidine dimer sharply increased with increased concentration of hydrogen ion, suggesting direct participation of hydrogen ion in dimer formations. In ESI-MS measurements of the solutions containing adenosine, cytidine, thymidine and guanosine, we observed protonated cytidine-guanosine dimer (CH+-G) and protonated cytidine-thymidine dimer (CH+-T) in addition to hemiprotonated cytidine-cytidine dimer (CH+-C) with following relative peak height, (CH+-C) > (CH+-G) ≈ (CH+-T) > (CH+-A). Additionally, in the ESI-MS measurements of solutions containing adenosine, thymidine and guanosine, we observed a considerable amount of protonated adenosine-guanosine (AH+-G) and protonated adenosine-thymidine (AH+-T).
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Affiliation(s)
- Riyoko Ishida
- Analytical Biochemistry, Wakayama Medical University, 580 Mikazura, Wakayama, Wakayama 641-0011, Japan
| | - Hideo Iwahashi
- Analytical Biochemistry, Wakayama Medical University, 580 Mikazura, Wakayama, Wakayama 641-0011, Japan
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16
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Schneider B, Božíková P, Nečasová I, Čech P, Svozil D, Černý J. A DNA structural alphabet provides new insight into DNA flexibility. Acta Crystallogr D Struct Biol 2018; 74:52-64. [PMID: 29372899 PMCID: PMC5786007 DOI: 10.1107/s2059798318000050] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/02/2018] [Indexed: 11/10/2022] Open
Abstract
DNA is a structurally plastic molecule, and its biological function is enabled by adaptation to its binding partners. To identify the DNA structural polymorphisms that are possible in such adaptations, the dinucleotide structures of 60 000 DNA steps from sequentially nonredundant crystal structures were classified and an automated protocol assigning 44 distinct structural (conformational) classes called NtC (for Nucleotide Conformers) was developed. To further facilitate understanding of the DNA structure, the NtC were assembled into the DNA structural alphabet CANA (Conformational Alphabet of Nucleic Acids) and the projection of CANA onto the graphical representation of the molecular structure was proposed. The NtC classification was used to define a validation score called confal, which quantifies the conformity between an analyzed structure and the geometries of NtC. NtC and CANA assignment were applied to analyze the structural properties of typical DNA structures such as Dickerson-Drew dodecamers, guanine quadruplexes and structural models based on fibre diffraction. NtC, CANA and confal assignment, which is accessible at the website https://dnatco.org, allows the quantitative assessment and validation of DNA structures and their subsequent analysis by means of pseudo-sequence alignment. An animated Interactive 3D Complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:Acta_Cryst_D:2.
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Affiliation(s)
- Bohdan Schneider
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Průmyslová 595, CZ-252 50 Vestec, Czechia
| | - Paulína Božíková
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Průmyslová 595, CZ-252 50 Vestec, Czechia
| | - Iva Nečasová
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Průmyslová 595, CZ-252 50 Vestec, Czechia
| | - Petr Čech
- Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology Prague, Technická 5, CZ-166 28 Prague, Czechia
| | - Daniel Svozil
- Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology Prague, Technická 5, CZ-166 28 Prague, Czechia
| | - Jiří Černý
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Průmyslová 595, CZ-252 50 Vestec, Czechia
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17
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Matsuura MF, Kim HJ, Takahashi D, Abboud KA, Benner SA. Crystal structures of deprotonated nucleobases from an expanded DNA alphabet. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2016; 72:952-959. [PMID: 27918296 DOI: 10.1107/s2053229616017071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/24/2016] [Indexed: 11/10/2022]
Abstract
Reported here is the crystal structure of a heterocycle that implements a donor-donor-acceptor hydrogen-bonding pattern, as found in the Z component [6-amino-5-nitropyridin-2(1H)-one] of an artificially expanded genetic information system (AEGIS). AEGIS is a new form of DNA from synthetic biology that has six replicable nucleotides, rather than the four found in natural DNA. Remarkably, Z crystallizes from water as a 1:1 complex of its neutral and deprotonated forms, and forms a `skinny' pyrimidine-pyrimidine pair in this structure. The pair resembles the known intercalated cytosine pair. The formation of the same pair in two different salts, namely poly[[aqua(μ6-2-amino-6-oxo-3-nitro-1,6-dihydropyridin-1-ido)sodium]-6-amino-5-nitropyridin-2(1H)-one-water (1/1/1)], denoted Z-Sod, {[Na(C5H4N3O3)(H2O)]·C5H5N3O3·H2O}n, and ammonium 2-amino-6-oxo-3-nitro-1,6-dihydropyridin-1-ide-6-amino-5-nitropyridin-2(1H)-one-water (1/1/1), denoted Z-Am, NH4+·C5H4N3O3-·C5H5N3O3·H2O, under two different crystallization conditions suggests that the pair is especially stable. Implications of this structure for the use of this heterocycle in artificial DNA are discussed.
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Affiliation(s)
- Mariko F Matsuura
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Hyo Joong Kim
- Foundation for Applied Molecular Evolution (FfAME), 13709 Progress Blvd, Box 17, Alachua, FL 32615, USA
| | - Daisuke Takahashi
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Khalil A Abboud
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Steven A Benner
- Foundation for Applied Molecular Evolution (FfAME), 13709 Progress Blvd, Box 17, Alachua, FL 32615, USA
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18
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Thirugnanasambandam A, Karthik S, Artheswari G, Gautham N. DNA polymorphism in crystals: three stable conformations for the decadeoxynucleotide d(GCATGCATGC). ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:780-8. [PMID: 27303798 DOI: 10.1107/s2059798316006306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/14/2016] [Indexed: 11/11/2022]
Abstract
High-resolution structures of DNA fragments determined using X-ray crystallography or NMR have provided descriptions of a veritable alphabet of conformations. They have also shown that DNA is a flexible molecule, with some sequences capable of adopting two different structures. Here, the first example is presented of a DNA fragment that can assume three different and distinct conformations in crystals. The decanucleotide d(GCATGCATGC) was previously reported to assume a single-stranded double-fold structure. In one of the two crystal structures described here the decamer assumes both the double-fold conformation and, simultaneously, the more conventional B-type double-helical structure. In the other crystal the sequence assumes the A-type double-helical conformation. These results, taken together with CD spectra, which were recorded as the decamer was titrated against four metal ions and spermine, indicate that the molecule may exist as a mixed population of structures in solution. Small differences in the environmental conditions, such as the concentration of metal ion, may decide which of these crystallizes out. The results also support the idea that it may be possible for DNA to change its structure to suit the binding requirements of proteins or drugs.
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Affiliation(s)
| | - Selvam Karthik
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Gunanithi Artheswari
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Namasivayam Gautham
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
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19
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Mitra SN, Biswas R, Shi K, Sundaralingam M. Crystal Structure of an RNA Duplex [r(gugcaca)dC](2) with 3'-Dinucleoside Overhangs Forming a Superhelix. J Biomol Struct Dyn 2016; 17 Suppl 1:189-94. [PMID: 22607423 DOI: 10.1080/07391102.2000.10506620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Abstract Crystal structure of the RNA octamer duplex, [r(gugcaca)dC] (2), with space group I2(1)2(1)2(1) and the cell constants a=24.29, b=45.25 and c=73.68Å, has been determined and refined. The structural and packing architecture of the molecule consist of a highly bent six base paired duplex forming a right-handed superhelix stacked in tandem compared to an infinite pseudo- continuous column as is usually present in RNA crystal structures. The super helix could be formed by the head-to-head stacking (g1 over g1 and g9 over g9), the large bend and the twists at the junctions may also be responsible. The sugar-phosphate backbones of the 3'-end dinucleoside overhangs snuggly fit into the minor grooves of adjacent double helical stacks. The 3'-terminal deoxycytidines form antiparallel hemiprotonated trans (C·C)(+) pairs with symmetry related deoxycytidines, while the penultimate adenines form base triples (a*g·c) with the capping g·c base pairs of the hexamer duplex with the adenine (a7) at one end being syn and at the other anti. These triple interactions are the same as those found in the tetrahymena ribozyme and group I intron.
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Affiliation(s)
- S N Mitra
- a Biological Macromolecular Structure Center, Departments of Chemistry and Biochemistry , The Ohio State University , 012 Rightmire Hall, 1060 Carmack Road , Columbus , OH , 43210
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20
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Affiliation(s)
- Sundus Erbas-Cakmak
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - David A. Leigh
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Charlie T. McTernan
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Alina
L. Nussbaumer
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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21
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Abstract
The base sequence in nucleic acids encodes substantial structural and functional information into the biopolymer. This encoded information provides the basis for the tailoring and assembly of DNA machines. A DNA machine is defined as a molecular device that exhibits the following fundamental features. (1) It performs a fuel-driven mechanical process that mimics macroscopic machines. (2) The mechanical process requires an energy input, "fuel." (3) The mechanical operation is accompanied by an energy consumption process that leads to "waste products." (4) The cyclic operation of the DNA devices, involves the use of "fuel" and "anti-fuel" ingredients. A variety of DNA-based machines are described, including the construction of "tweezers," "walkers," "robots," "cranes," "transporters," "springs," "gears," and interlocked cyclic DNA structures acting as reconfigurable catenanes, rotaxanes, and rotors. Different "fuels", such as nucleic acid strands, pH (H⁺/OH⁻), metal ions, and light, are used to trigger the mechanical functions of the DNA devices. The operation of the devices in solution and on surfaces is described, and a variety of optical, electrical, and photoelectrochemical methods to follow the operations of the DNA machines are presented. We further address the possible applications of DNA machines and the future perspectives of molecular DNA devices. These include the application of DNA machines as functional structures for the construction of logic gates and computing, for the programmed organization of metallic nanoparticle structures and the control of plasmonic properties, and for controlling chemical transformations by DNA machines. We further discuss the future applications of DNA machines for intracellular sensing, controlling intracellular metabolic pathways, and the use of the functional nanostructures for drug delivery and medical applications.
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22
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Mata G, Luedtke NW. Fluorescent Probe for Proton-Coupled DNA Folding Revealing Slow Exchange of i-Motif and Duplex Structures. J Am Chem Soc 2015; 137:699-707. [DOI: 10.1021/ja508741u] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Guillaume Mata
- Department of Chemistry, University of Zürich, Winterthurerstrasse
190, CH-8057 Zürich, Switzerland
| | - Nathan W. Luedtke
- Department of Chemistry, University of Zürich, Winterthurerstrasse
190, CH-8057 Zürich, Switzerland
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23
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Liu G, Li Z, Zhu J, Liu Y, Zhou Y, He J. Studies on the thymine–mercury–thymine base pairing in parallel and anti-parallel DNA duplexes. NEW J CHEM 2015. [DOI: 10.1039/c5nj01859e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Parallel and anti-parallel T–Hg–T base pairs have different thermal stabilities and conformational influences on DNA duplex structures.
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Affiliation(s)
- Gaofeng Liu
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Zhiwen Li
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Junfei Zhu
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Yang Liu
- School of Pharmacological Sciences
- Guangxi Medical University
- Nanning 530021
- China
| | - Ying Zhou
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Junlin He
- Beijing Institute of Pharmacology and Toxicology
- Beijing 100850
- China
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24
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Huang H, Hong X, Liu F, Li N. A simple approach to study the conformational switching of i-motif DNA by fluorescence anisotropy. Analyst 2015; 140:5987-91. [DOI: 10.1039/c5an01011j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Fluorescence anisotropy is a simple, reliable and sensitive approach to study the conformational switching of the i-motif structure.
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Affiliation(s)
- Hongduan Huang
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education
- Institute of Analytical Chemistry
- College of Chemistry and Molecular Engineering
- Peking University
| | - Xinying Hong
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education
- Institute of Analytical Chemistry
- College of Chemistry and Molecular Engineering
- Peking University
| | - Feng Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education
- Institute of Analytical Chemistry
- College of Chemistry and Molecular Engineering
- Peking University
| | - Na Li
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education
- Institute of Analytical Chemistry
- College of Chemistry and Molecular Engineering
- Peking University
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25
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Chen YW, Jhan CR, Neidle S, Hou MH. Structural Basis for the Identification of an i-Motif Tetraplex Core with a Parallel-Duplex Junction as a Structural Motif in CCG Triplet Repeats. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201405637] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Chen YW, Jhan CR, Neidle S, Hou MH. Structural basis for the identification of an i-motif tetraplex core with a parallel-duplex junction as a structural motif in CCG triplet repeats. Angew Chem Int Ed Engl 2014; 53:10682-6. [PMID: 25139267 DOI: 10.1002/anie.201405637] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Indexed: 11/12/2022]
Abstract
CCG triplet repeats can fold into tetraplex structures, which are associated with the expansion of (CCG)n trinucleotide sequences in certain neurological diseases. These structures are stabilized by intertwining i-motifs. However, the structural basis for tetraplex i-motif formation in CCG triplet repeats remains largely unknown. We report the first crystal structure of a CCG-repeat sequence, which shows that two dT(CCG)3 A strands can associate to form a tetraplex structure with an i-motif core containing four C:C(+) pairs flanked by two G:G homopurine base pairs as a structural motif. The tetraplex core is attached to a short parallel-stranded duplex. Each hairpin itself contains a central CCG loop in which the nucleotides are flipped out and stabilized by stacking interactions. The helical twists between adjacent cytosine residues of this structure in the i-motif core have an average value of 30°, which is greater than those previously reported for i-motif structures.
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Affiliation(s)
- Yi-Wen Chen
- Institute of Genomics and Bioinformatics and Institute of Biochemistry, National Chung Hsing University, No. 250 Kuo-Kuang Road, Taichung (Taiwan)
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27
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Day HA, Pavlou P, Waller ZAE. i-Motif DNA: structure, stability and targeting with ligands. Bioorg Med Chem 2014; 22:4407-18. [PMID: 24957878 DOI: 10.1016/j.bmc.2014.05.047] [Citation(s) in RCA: 271] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/09/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
Abstract
i-Motifs are four-stranded DNA secondary structures which can form in sequences rich in cytosine. Stabilised by acidic conditions, they are comprised of two parallel-stranded DNA duplexes held together in an antiparallel orientation by intercalated, cytosine-cytosine(+) base pairs. By virtue of their pH dependent folding, i-motif forming DNA sequences have been used extensively as pH switches for applications in nanotechnology. Initially, i-motifs were thought to be unstable at physiological pH, which precluded substantial biological investigation. However, recent advances have shown that this is not always the case and that i-motif stability is highly dependent on factors such as sequence and environmental conditions. In this review, we discuss some of the different i-motif structures investigated to date and the factors which affect their topology, stability and dynamics. Ligands which can interact with these structures are necessary to aid investigations into the potential biological functions of i-motif DNA and herein we review the existing i-motif ligands and give our perspective on the associated challenges with targeting this structure.
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Affiliation(s)
- Henry A Day
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Pavlos Pavlou
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Zoë A E Waller
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK.
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28
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Wang F, Lu CH, Willner I. From cascaded catalytic nucleic acids to enzyme-DNA nanostructures: controlling reactivity, sensing, logic operations, and assembly of complex structures. Chem Rev 2014; 114:2881-941. [PMID: 24576227 DOI: 10.1021/cr400354z] [Citation(s) in RCA: 494] [Impact Index Per Article: 49.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Fuan Wang
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
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29
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El-Sayed AA, Pedersen EB, Khaireldin NA. Studying the influence of the pyrene intercalator TINA on the stability of DNA i-motifs. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2014; 31:872-9. [PMID: 23215550 DOI: 10.1080/15257770.2012.742199] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Certain cytosine-rich (C-rich) DNA sequences can fold into secondary structures as four-stranded i-motifs with hemiprotonated base pairs. Here we synthesized C-rich TINA-intercalating oligonucleotides by inserting a nonnucleotide pyrene moiety between two C-rich regions. The stability of their i-motif structures was studied by using UV melting temperature measurements and circular dichroism spectra at different pH values under noncrowding and crowding conditions (20% poly(ethylene glycol)). When TINA ((R)-3-((4-(1-pyrenylethynyl)benzyl)oxy) propane-1,2-diol) is inserted, the oligonucleotides could form an i-motif at a higher pH than observed for the corresponding wildtype oligonucleotide.
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Affiliation(s)
- Ahmed A El-Sayed
- Nucleic Acid Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, Denmark
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30
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Benabou S, Aviñó A, Eritja R, González C, Gargallo R. Fundamental aspects of the nucleic acid i-motif structures. RSC Adv 2014. [DOI: 10.1039/c4ra02129k] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The latest research on fundamental aspects of i-motif structures is reviewed with special attention to their hypothetical rolein vivo.
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Affiliation(s)
- S. Benabou
- Department of Analytical Chemistry
- University of Barcelona
- E-08028 Barcelona, Spain
| | - A. Aviñó
- Institute for Advanced Chemistry of Catalonia (IQAC-CSIC)
- CIBER-BBN Networking Centre on Bioengineering
- Biomaterials and Nanomedicine
- E-08034 Barcelona, Spain
| | - R. Eritja
- Institute for Advanced Chemistry of Catalonia (IQAC-CSIC)
- CIBER-BBN Networking Centre on Bioengineering
- Biomaterials and Nanomedicine
- E-08034 Barcelona, Spain
| | - C. González
- Institute of Physical Chemistry “Rocasolano”
- CSIC
- E-28006 Madrid, Spain
| | - R. Gargallo
- Department of Analytical Chemistry
- University of Barcelona
- E-08028 Barcelona, Spain
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31
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Choi J, Tanaka A, Cho DW, Fujitsuka M, Majima T. Efficient Electron Transfer in i-Motif DNA with a Tetraplex Structure. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201306017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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Choi J, Tanaka A, Cho DW, Fujitsuka M, Majima T. Efficient Electron Transfer in i-Motif DNA with a Tetraplex Structure. Angew Chem Int Ed Engl 2013; 52:12937-41. [DOI: 10.1002/anie.201306017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/11/2013] [Indexed: 11/08/2022]
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33
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Cui J, Waltman P, Le VH, Lewis EA. The effect of molecular crowding on the stability of human c-MYC promoter sequence I-motif at neutral pH. Molecules 2013; 18:12751-67. [PMID: 24132198 PMCID: PMC6270392 DOI: 10.3390/molecules181012751] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/26/2013] [Accepted: 10/10/2013] [Indexed: 12/20/2022] Open
Abstract
We have previously shown that c-MYC promoter sequences can form stable i-motifs in acidic solution (pH 4.5-5.5). In terms of drug targeting, the question is whether c-MYC promoter sequence i-motifs will exist in the nucleus at neutral pH. In this work, we have investigated the stability of a mutant c-MYC i-motif in solutions containing a molecular crowding agent. The crowded nuclear environment was modeled by the addition of up to 40% w/w polyethylene glycols having molecular weights up to 12,000 g/mol. CD and DSC were used to establish the presence and stability of c-MYC i-motifs in buffer solutions over the pH range 4 to 7. We have shown that the c-MYC i-motif can exist as a stable structure at pH values as high as 6.7 in crowded solutions. Generic dielectric constant effects, e.g., a shift in the pKa of cytosine by more than 2 units (e.g., 4.8 to 7.0), or the formation of non-specific PEG/DNA complexes appear to contribute insignificantly to i-motif stabilization. Molecular crowding, largely an excluded volume effect of added PEG, having a molecular weight in excess of 1,000 g/mol, appears to be responsible for stabilizing the more compact i-motif over the random coil at higher pH values.
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Affiliation(s)
- Jingjing Cui
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA.
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34
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Wu S, Wang X, Ye X, Zhang G. pH-Induced conformational change and dimerization of DNA chains investigated by analytical ultracentrifugation. J Phys Chem B 2013; 117:11541-7. [PMID: 24010411 DOI: 10.1021/jp405561f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
pH-induced conformational change of i-motif DNA has been studied by analytical ultracentrifugation. As pH increases, the hydrodynamic radius of individual DNA chains in aqueous solutions prepared by being heat-treated suddenly increases while the molar mass is constant, indicating that the conformation changes from an i-motif to a random coil. When DNA concentrations are higher than 1.0 μM, relatively stable dimers are formed as pH sharply decreases from 7.5 to 4.5. Moreover, the weight percentage of the dimers increases with the initial DNA concentration. The study can help to understand the functions of the telomeres containing repeated cytosine-rich sequences and to develop DNA-based devices.
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Affiliation(s)
- Sha Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
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35
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DNA nanotechnology with one-dimensional self-assembled nanostructures. Curr Opin Biotechnol 2013; 24:562-74. [PMID: 23477850 DOI: 10.1016/j.copbio.2013.02.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 02/07/2013] [Accepted: 02/08/2013] [Indexed: 01/22/2023]
Abstract
The information encoded in the base sequence of DNA provides substantial structural and functional information for the instructive self-assembly of one-dimensional (1D) functional DNA nanostructures. The hybridization chain reaction (HCR) and the formation of HCR-stimulated DNAzyme nanochains are presented, as a means to develop amplified DNA sensors and aptasensors. Similarly, the rolling circle amplification (RCA) process is implemented to generate 1D DNA nanochains consisting of constant repeat units being implemented for the amplified sensing (using DNAzymes as repeat units) and for the switchable control of electron transfer at electrodes. 1D DNA nanostructures are used as templates for the programmed positioning of enzymes that enable the activation of enzyme cascades and the biocatalytic growth of metallic nanowires. The future perspectives of the self-assembly mechanisms are discussed.
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36
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Choi J, Majima T. Reversible conformational switching of i-motif DNA studied by fluorescence spectroscopy. Photochem Photobiol 2013; 89:513-22. [PMID: 23311444 DOI: 10.1111/php.12042] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 01/04/2013] [Indexed: 12/19/2022]
Abstract
Non-B DNAs, which can form unique structures other than double helix of B-DNA, have attracted considerable attention from scientists in various fields including biology, chemistry and physics etc. Among them, i-motif DNA, which is formed from cytosine (C)-rich sequences found in telomeric DNA and the promoter region of oncogenes, has been extensively investigated as a signpost and controller for the oncogene expression at the transcription level and as a promising material in nanotechnology. Fluorescence techniques such as fluorescence resonance energy transfer (FRET) and the fluorescence quenching are important for studying DNA and in particular for the visualization of reversible conformational switching of i-motif DNA that is triggered by the protonation. Here, we review the latest studies on the conformational dynamics of i-motif DNA as well as the application of FRET and fluorescence quenching techniques to the visualization of reversible conformational switching of i-motif DNA in nano-biotechnology.
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Affiliation(s)
- Jungkweon Choi
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Osaka, Japan
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Mei H, Budow S, Seela F. Construction and assembly of chimeric DNA: oligonucleotide hybrid molecules composed of parallel or antiparallel duplexes and tetrameric i-motifs. Biomacromolecules 2012; 13:4196-204. [PMID: 23121010 DOI: 10.1021/bm301471d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Chimeric DNA containing parallel (ps) and antiparallel (aps) duplex elements as well as poly-dC tracts were designed and synthesized. Oligonucleotide duplexes with ps chain orientation containing reverse Watson-Crick dA-dT base pairs and short d(C)2 tails are stabilized under slightly acidic conditions by hemiprotonated dCH+-dC base pairs ("clamp" effect). Corresponding molecules with aps orientation containing Watson-Crick dA-dT base pairs do not show this phenomenon. Chimeric DNA with ps duplex elements and long d(C)5 tails at one or at both ends assemble to tetrameric i-motif structures. Molecules with two terminal d(C)5 tails form multimeric assemblies which have the potential to form nanoscopic scaffolds. A preorganization of the ps duplex chains stabilizes the i-motif assemblies up to almost neutral conditions as evidenced by thermal melting and gel electrophoresis. Although, ps DNA is generally less stable than aps DNA, the aps duplexes contribute less to the stability of the i-motif than ps DNA.
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Affiliation(s)
- Hui Mei
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstraße 11, 48149 Münster, Germany
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38
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Abstract
The physicochemical properties of small molecules as well as macromolecules are modulated by solution pH, and DNA is no exception. Special sequences of DNA can adopt unusual conformations e.g., triplex, i-motif and A-motif, depending on solution pH. The specific range of pH for these unusual structures is dictated by the pKa of protonation of the relevant nucleobase involved in the resultant non-canonical base pairing that is required to stabilise the structure. The biological significance of these pH-dependent structures is not yet clear. However, these non-B-DNA structures have been used to design different devices to direct chemical reactions, generate mechanical force, sense pH, etc. The performance of these devices can be monitored by a photonic signal. They are autonomous and their ‘waste free’ operation cycles makes them highly processive. Applications of these devices help to increase understanding of the structural polymorphism of the motifs themselves. The design of these devices has continuously evolved to improve their performance efficiency in different contexts. In some examples, these devices have been shown to perform inside complex living systems with similar efficiencies, to report on the chemical environment there. The robust performance of these devices opens up exciting possibilities for pH-sensitive DNA devices in the study of various pH-regulated biological events.
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Affiliation(s)
- Sonali Saha
- National Centre for Biological Sciences TIFR, GKVK, Bellary Road, Bangalore 560065 India
| | - Yamuna Krishnan*
- National Centre for Biological Sciences TIFR, GKVK, Bellary Road, Bangalore 560065 India
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39
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Yang Y, Sun Y, Yang Y, Xing Y, Zhang T, Wang Z, Yang Z, Liu D. Influence of Tetra(ethylene glycol) (EG4) Substitution at the Loop Region on the Intramolecular DNA i-Motif. Macromolecules 2012. [DOI: 10.1021/ma300230q] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuhe Yang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yawei Sun
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Yang Yang
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Yongzheng Xing
- Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Tao Zhang
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Zeming Wang
- Department of Chemistry, University of Science and Technology of China, Hefei
230026, China
| | - Zhongqiang Yang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Dongsheng Liu
- Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
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40
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Affiliation(s)
- Ofer I. Wilner
- Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Itamar Willner
- Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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41
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Lieblein AL, Buck J, Schlepckow K, Fürtig B, Schwalbe H. Time-resolved NMR spectroscopic studies of DNA i-motif folding reveal kinetic partitioning. Angew Chem Int Ed Engl 2011; 51:250-3. [PMID: 22095623 DOI: 10.1002/anie.201104938] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/12/2011] [Indexed: 11/08/2022]
Affiliation(s)
- Anna Lena Lieblein
- Institute for Organic Chemistry and Chemical Biology, Center of Biomolecular Magnetic Resonance, Johann Wolfgang Goethe-University Frankfurt/Main, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
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42
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Lieblein AL, Buck J, Schlepckow K, Fürtig B, Schwalbe H. Zeitaufgelöste NMR-Untersuchungen zeigen einen kinetischen Partitionierungsmechanismus während der Faltung des DNA-i-Motivs. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201104938] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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43
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Balaeff A, Craig SL, Beratan DN. B-DNA to zip-DNA: simulating a DNA transition to a novel structure with enhanced charge-transport characteristics. J Phys Chem A 2011; 115:9377-91. [PMID: 21598926 PMCID: PMC3615717 DOI: 10.1021/jp110871g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The forced extension of a DNA segment is studied in a series of steered molecular dynamics simulations, employing a broad range of pulling forces. Throughout the entire force range, the formation of a zipper-like (zip-) DNA structure is observed. In that structure, first predicted by Lohikoski et al., the bases of the DNA strands interdigitate with each other and form a single-base aromatic stack. Similar motifs, albeit only a few base pairs in extent, have been observed in experimental crystal structures. Analysis of the dynamics of structural changes in pulled DNA shows that S-form DNA, thought to be adopted by DNA under applied force, serves as an intermediate between B-DNA and zip-DNA. Therefore, the phase transition plateau observed in force-extension curves of DNA is suggested to reflect the B-DNA to zip-DNA structural transition. Electronic structure analysis of purine bases in zip-DNA indicates a several-fold to order of magnitude increase in the π-π electronic coupling among nearest-neighbor nucleobases, compared to B-DNA. We further observe that zip-DNA does not require base pair complementarity between DNA strands, and we predict that the increased electronic coupling in zip-DNA will result in a much higher rate of charge transfer through an all-purine zip-DNA compared to B-DNA of equal length.
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Affiliation(s)
- Alexander Balaeff
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
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Dettler JM, Buscaglia R, Le VH, Lewis EA. DSC deconvolution of the structural complexity of c-MYC P1 promoter G-quadruplexes. Biophys J 2011; 100:1517-25. [PMID: 21402034 DOI: 10.1016/j.bpj.2011.01.068] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 01/21/2011] [Accepted: 01/25/2011] [Indexed: 01/01/2023] Open
Abstract
We completed a biophysical characterization of the c-MYC proto-oncogene P1 promoter quadruplex and its interaction with a cationic porphyrin, 5,10,15,20-tetra(N-methyl-4-pyridyl)porphyrin (TMPyP4), using differential scanning calorimetry, isothermal titration calorimetry, and circular dichroism spectroscopy. We examined three different 24-mer oligonucleotides, including the wild-type (WT) sequence found in the c-MYC P(1) promoter and two mutant G→T sequences that are known to fold into single 1:2:1 and 1:6:1 loop isomer quadruplexes. Biophysical experiments were performed on all three oligonucleotide sequences at two different ionic strengths (30 mM [K(+)] and 130 mM [K(+)]). Differential scanning calorimetry experiments demonstrated that the WT quadruplex consists of a mixture of at least two different folded conformers at both ionic strengths, whereas both mutant sequences exhibit a single two-state melting transition at both ionic strengths. Isothermal titration calorimetry experiments demonstrated that both mutant sequences bind 4 mols of TMPyP4 to 1 mol of DNA, in similarity to the WT sequence. The circular dichroism spectroscopy signatures for all three oligonucleotides at both ionic strengths are consistent with an intramolecular parallel stranded G-quadruplex structure, and no change in quadruplex structure is observed upon addition of saturating amounts of TMPyP4 (i.e., 4:1 TMPyP4/DNA).
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Affiliation(s)
- Jamie M Dettler
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, USA
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45
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Zikich D, Liu K, Sagiv L, Porath D, Kotlyar A. I-motif nanospheres: unusual self-assembly of long cytosine strands. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:1029-34. [PMID: 21381197 DOI: 10.1002/smll.201002213] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Revised: 01/14/2011] [Indexed: 05/25/2023]
Abstract
The synthesis and characterization of novel DNA structures based on tetraplex cytosine (C) arrangements, known as i-motifs or i-tetraplexes, is reported. Atomic force microscopy (AFM) investigation shows that long C-strands in mild acidic conditions form compact spherically shaped nanostructures. The DNA nanospheres are characterized by a typical uniform shape and narrow height distribution. Electrostatic force microscopy (EFM) measurements performed on the i-motif spheres clearly show their electrical polarizability. Further investigations by scanning tunneling microscopy (STM) at ultrahigh vacuum reveals that the structures exhibit an average voltage gap of 1.9 eV, which is narrower than the voltage gap previously measured for poly(dG)-poly(dC) molecules in similar conditions.
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Affiliation(s)
- Dragoslav Zikich
- Department of Biochemistry George S. Wise Faculty of Life Sciences, Tel Aviv University Ramat Aviv 69978, Israel
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46
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Chawla M, Sharma P, Halder S, Bhattacharyya D, Mitra A. Protonation of base pairs in RNA: context analysis and quantum chemical investigations of their geometries and stabilities. J Phys Chem B 2011; 115:1469-84. [PMID: 21254753 DOI: 10.1021/jp106848h] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Base pairs involving protonated nucleobases play important roles in mediating global macromolecular conformational changes and in facilitation of catalysis in a variety of functional RNA molecules. Here we present our attempts at understanding the role of such base pairs by detecting possible protonated base pairs in the available RNA crystal structures using BPFind software, in their specific structural contexts, and by the characterization of their geometries, interaction energies, and stabilities using advanced quantum chemical computations. We report occurrences of 18 distinct protonated base pair combinations from a representative data set of RNA crystal structures and propose a theoretical model for one putative base pair combination. Optimization of base pair geometries was carried out at the B3LYP/cc-pVTZ level, and the BSSE corrected interaction energies were calculated at the MP2/aug-cc-pVDZ level of theory. The geometries for each of the base pairs were characterized in terms of H-bonding patterns observed, rmsd values observed on optimization, and base pair geometrical parameters. In addition, the intermolecular interaction in these complexes was also analyzed using Morokuma energy decomposition. The gas phase interaction energies of the base pairs range from -24 to -49 kcal/mol and reveal the dominance of Hartree-Fock component of interaction energy constituting 73% to 98% of the total interaction energy values. On the basis of our combined bioinformatics and quantum chemical analysis of different protonated base pairs, we suggest resolution of structural ambiguities and correlate their geometric and energetic features with their structural and functional roles. In addition, we also examine the suitability of specific base pairs as key elements in molecular switches and as nucleators for higher order structures such as base triplets and quartets.
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Affiliation(s)
- Mohit Chawla
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H) Gachibowli, Hyderabad 500032, India
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47
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Shimron S, Magen N, Elbaz J, Willner I. pH-programmable DNAzyme nanostructures. Chem Commun (Camb) 2011; 47:8787-9. [DOI: 10.1039/c1cc12795k] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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Dettler JM, Buscaglia R, Cui J, Cashman D, Blynn M, Lewis EA. Biophysical characterization of an ensemble of intramolecular i-motifs formed by the human c-MYC NHE III1 P1 promoter mutant sequence. Biophys J 2010; 99:561-7. [PMID: 20643075 DOI: 10.1016/j.bpj.2010.04.042] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 03/16/2010] [Accepted: 04/05/2010] [Indexed: 10/19/2022] Open
Abstract
i-Motif-forming sequences are present in or near the regulatory regions of >40% of all genes, including known oncogenes. We report here the results of a biophysical characterization and computational study of an ensemble of intramolecular i-motifs that model the polypyrimidine sequence in the human c-MYC P1 promoter. Circular dichroism results demonstrate that the mutant sequence (5'-CTT TCC TAC CCTCCC TAC CCT AA-3') can adopt multiple "i-motif-like," classical i-motif, and single-stranded structures as a function of pH. The classical i-motif structures are predominant in the pH range 4.2-5.2. The "i-motif-like" and single-stranded structures are the most significant species in solution at pH higher and lower, respectively, than that range. Differential scanning calorimetry results demonstrate an equilibrium mixture of at least three i-motif folded conformations with Tm values of 38.1, 46.6, and 49.5 degrees C at pH 5.0. The proposed ensemble of three folded conformations includes the three lowest-energy conformations obtained by computational modeling and two folded conformers that were proposed in a previous NMR study. The NMR study did not report the most stable conformer found in this study.
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Affiliation(s)
- Jamie M Dettler
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, USA
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49
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Kendrick S, Hurley LH. The role of G-quadruplex/i-motif secondary structures as cis-acting regulatory elements. ACTA ACUST UNITED AC 2010; 82:1609-1621. [PMID: 21796223 DOI: 10.1351/pac-con-09-09-29] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The nature of DNA has captivated scientists for more than fifty years. The discovery of the double-helix model of DNA by Watson and Crick in 1953 not only established the primary structure of DNA, but also provided the mechanism behind DNA function. Since then, researchers have continued to further the understanding of DNA structure and its pivotal role in transcription. The demonstration of DNA secondary structure formation has allowed for the proposal that the dynamics of DNA itself can function to modulate transcription. This review presents evidence that DNA can exist in a dynamic equilibrium between duplex and secondary conformations. In addition, data demonstrating that intracellular proteins as well as small molecules can shift this equilibrium in either direction to alter gene transcription will be discussed, with a focus on the modulation of proto-oncogene expression.
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50
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Kendrick S, Akiyama Y, Hecht SM, Hurley LH. The i-motif in the bcl-2 P1 promoter forms an unexpectedly stable structure with a unique 8:5:7 loop folding pattern. J Am Chem Soc 2010; 131:17667-76. [PMID: 19908860 DOI: 10.1021/ja9076292] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Transcriptional regulation of the bcl-2 proto-oncogene is highly complex, with the majority of transcription driven by the P1 promoter site and the interaction of multiple regulatory proteins. A guanine- and cytosine-rich (GC-rich) region directly upstream of the P1 site has been shown to be integral to bcl-2 promoter activity, as deletion or mutation of this region significantly increases transcription. This GC-rich element consists of six contiguous runs of guanines and cytosines that have the potential to adopt DNA secondary structures, the G-quadruplex and i-motif, respectively. Our laboratory has previously demonstrated that the polypurine-rich strand of the bcl-2 promoter can form a mixture of three different G-quadruplex structures. In this current study, we demonstrate that the complementary polypyrimidine-rich strand is capable of forming one major intramolecular i-motif DNA secondary structure with a transition pH of 6.6. Characterization of the i-motif folding pattern using mutational studies coupled with circular dichroic spectra and thermal stability analyses revealed an 8:5:7 loop conformation as the predominant structure at pH 6.1. The folding pattern was further supported by chemical footprinting with bromine. In addition, a novel assay involving the sequential incorporation of a fluorescent thymine analog at each thymine position provided evidence of a capping structure within the top loop region of the i-motif. The potential of the GC-rich element within the bcl-2 promoter region to form DNA secondary structures suggests that the transition from the B-DNA to non-B-DNA conformation may play an important role in bcl-2 transcriptional regulation. Furthermore, the two adjacent large lateral loops in the i-motif structure provide an unexpected opportunity for protein and small molecule recognition.
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Affiliation(s)
- Samantha Kendrick
- Arizona Cancer Center, 1515 North Campbell Avenue, Tucson, Arizona 85724, USA
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