151
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Rogers RA, Fleming AM, Burrows CJ. Unusual Isothermal Hysteresis in DNA i-Motif pH Transitions: A Study of the RAD17 Promoter Sequence. Biophys J 2019; 114:1804-1815. [PMID: 29694860 DOI: 10.1016/j.bpj.2018.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/07/2018] [Accepted: 03/14/2018] [Indexed: 11/15/2022] Open
Abstract
We have interrogated the isothermal folding behavior of the DNA i-motif of the human telomere, dC19, and a high-stability i-motif-forming sequence in the promoter of the human DNA repair gene RAD17 using human physiological solution and temperature conditions. We developed a circular-dichroism-spectroscopy-based pH titration method that is followed by analysis of titration curves in the derivative domain and found that the observed pH-dependent folding behavior can be significantly different and, in some cases, multiphasic, with a dependence on how rapidly i-motif folding is induced. Interestingly, the human telomere sequence exhibits unusual isothermal hysteresis in which the unfolding process always occurs at a higher pH than the folding process. For the RAD17 i-motif, rapid folding by injection into a low-pH solution results in triphasic unfolding behavior that is completely diminished when samples are slowly folded in a stepwise manner via pH titration. Chemical footprinting of the RAD17 sequence and pH titrations of dT-substituted mutants of the RAD17 sequence were used to develop a model of RAD17 folding and unfolding. These results may provide valuable information pertinent to i-motif use in sensors and materials, as well as insight into the potential biological activity of i-motif-forming sequences under stepwise or instantaneous changes in pH.
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Affiliation(s)
- R Aaron Rogers
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - Aaron M Fleming
- Department of Chemistry, University of Utah, Salt Lake City, Utah
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152
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Zhang Y, Pan V, Li X, Yang X, Li H, Wang P, Ke Y. Dynamic DNA Structures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900228. [PMID: 30970183 PMCID: PMC7252325 DOI: 10.1002/smll.201900228] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/20/2019] [Indexed: 05/19/2023]
Abstract
Dynamic DNA structures, a type of DNA construct built using programmable DNA self-assembly, have the capability to reconfigure their conformations in response to environmental stimulation. A general strategy to design dynamic DNA structures is to integrate reconfigurable elements into conventional static DNA structures that may be assembled from a variety of methods including DNA origami and DNA tiles. Commonly used reconfigurable elements range from strand displacement reactions, special structural motifs, target-binding DNA aptamers, and base stacking components, to DNA conformational change domains, etc. Morphological changes of dynamic DNA structures may be visualized by imaging techniques or may be translated to other detectable readout signals (e.g., fluorescence). Owing to their programmable capability of recognizing environmental cues with high specificity, dynamic DNA structures embody the epitome of robust and versatile systems that hold great promise in sensing and imaging biological analytes, in delivering molecular cargos, and in building programmable systems that are able to conduct sophisticated tasks.
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Affiliation(s)
- Yingwei Zhang
- Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Victor Pan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Xue Li
- Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Xueqin Yang
- Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Haofei Li
- Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Pengfei Wang
- Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Yonggang Ke
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
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153
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Detection of nucleotide sequences capable of forming non-canonical DNA structures: Application of automata theory. Comput Biol Chem 2019; 80:278-283. [PMID: 31054540 DOI: 10.1016/j.compbiolchem.2019.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 11/24/2022]
Abstract
In this study, we develop a program that allows us to reveal DNA receptors, i.e. nucleotide sequences that may form more than one non-canonical structure. The data obtained may be analysed either experimentally or using DNA banks, and refers to the coding, non-coding or promotor region of the gene. These results provide a better understanding of the role that non-canonical structures play in pathological modifications of the genetic apparatus, resulting in tumour formation or inherited disease. They also reveal the effect of single nucleotide polymorphisms on gene expression, indicate so-called "risk regions" in which the substitution of a single nucleotide may lead to increased formation of non-canonical structures, and elucidate the epigenetic mechanisms of microorganism adaptation.
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154
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Park JJ, Han SY. Alternated Branching Ratios by Anomaly in Collision-Induced Dissociation of Proton-Bound Hoogsteen Base Pairs of 1-Methylcytosine with 1-Methylguanine and 9-Methylguanine. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:846-854. [PMID: 30911905 DOI: 10.1007/s13361-019-02161-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/26/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
A comparative study on the proton-bound complexes of 1-methylcytosine (1-mC) with 1-methylguanine (1-mG) and 9-methylguanine (9-mG), [1-mC:1-mG:H]+ and [1-mC:9-mG:H]+, respectively, was carried out using energy-resolved collision-induced dissociation (ER-CID) experiments in combination with quantum chemical calculations. In ER-CID experiments, the measured survival yields indicated an essentially identical stability for the two proton-bound complexes. In comparison with the lowest-energy structures and base-pairing energetics predicted at the B3LYP/6-311+G(2d,2p) theory level, both complexes produced in this study were suggested to be proton-bound Hoogsteen base pairs. Curiously, despite the similarity in structures, binding energetics, and potential energy surfaces predicted by the B3LYP theory, the fragment branching ratios exhibited an intriguing alternation between the two proton-bound Hoogsteen base pairs. The CID of [1-mC:1-mG:H]+ produced protonated cytosines, [1-mC:H]+, more abundantly than [1-mG:H]+, whereas that of [1-mC:9-mG:H]+ gave rise to a more pronounced production of protonated guanines, [9-mG:H]+. However, using the proton affinities of moieties predicted by the high-accuracy methods, including CBS-QB3 and the Guassian-4 theory, the anomaly known for [Cytosine:Guanine:H]+ (J. Am. Soc. Mass Spectrom. 29, 2368-2379 (2018)) successfully accounted for the alternated branching ratios. Thereby, the anomaly, more specifically, the production of proton-transferred fragments of O-protonated cytosines in the CID of proton-bound Hoogsteen base pairs, is indeed real, which is disclosed as the alternated branching ratios in the CID spectra of [1-mC:1-mG:H]+ and [1-mC:9-mG:H]+ in this study. Graphical Abstract .
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Affiliation(s)
- Jeong Ju Park
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Sang Yun Han
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.
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155
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Tsvetkov VB, Zatsepin TS, Turaev AV, Farzan VM, Pozmogova GE, Aralov AV, Varizhuk AM. DNA i-Motifs With Guanidino- i-Clamp Residues: The Counterplay Between Kinetics and Thermodynamics and Implications for the Design of pH Sensors. Comput Struct Biotechnol J 2019; 17:527-536. [PMID: 31049164 PMCID: PMC6479070 DOI: 10.1016/j.csbj.2019.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 11/12/2022] Open
Abstract
I-motif structures, adopted by cytosine-rich DNA strands, have attracted considerable interest as possible regulatory elements in genomes. Applied science exploits the advantages of i-motif stabilization under acidic conditions: i-motif-based pH sensors and other biocompatible nanodevices are being developed. Two key characteristics of i-motifs as core elements of nanodevices, i.e., their stability under physiological conditions and folding/unfolding rates, still need to be improved. We have previously reported a phenoxazine derivative (i-clamp) that enhances the thermal stability of the i-motif and shifts the pH transition point closer to physiological values. Here, we performed i-clamp guanidinylation to further explore the prospects of clamp-like modifications in i-motif fine-tuning. Based on molecular modeling data, we concluded that clamp guanidinylation facilitated interstrand interactions in an i-motif core and ultimately stabilized the i-motif structure. We tested the effects of guanidino-i-clamp insertions on the thermal stabilities of genomic and model i-motifs. We also investigated the folding/unfolding kinetics of native and modified i-motifs under moderate, physiologically relevant pH alterations. We demonstrated fast folding/unfolding of native genomic and model i-motifs in response to pH stimuli. This finding supports the concept of i-motifs as possible genomic regulatory elements and encourages the future design of rapid-response pH probes based on such structures. Incorporation of guanidino-i-clamp residues at/near the 5′-terminus of i-motifs dramatically decreased the apparent unfolding rates and increased the thermal stabilities of the structures. This counterplay between the effects of modifications on i-motif stability and their effects on kinetics should be taken into account in the design of pH sensors.
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Affiliation(s)
- Vladimir B Tsvetkov
- Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia.,I.M. Sechenov First Moscow State Medical University, Trubetskaya Str. 8-2, 119991 Moscow, Russia.,Research Institute of Influenza, Professora Popova str., 15/17, Sankt-Peterburg 197376, Russia
| | - Timofei S Zatsepin
- Skolkovo Institute of Science and Technology, Skolkovo, 143026 Moscow, Russia.,Lomonosov Moscow State University, Department of Chemistry, Leninskie Gory Str. 1-3, 119992 Moscow, Russia
| | - Anton V Turaev
- Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia.,Moscow Institute of Physics and Technology, Institutsky lane 9, Dolgoprudny 141700, Russia
| | - Valentina M Farzan
- Skolkovo Institute of Science and Technology, Skolkovo, 143026 Moscow, Russia
| | - Galina E Pozmogova
- Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia.,Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky prospect, 33, build. 2, Moscow 119071, Russia
| | - Andrey V Aralov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russia
| | - Anna M Varizhuk
- Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, Moscow 119991, Russia
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156
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Abstract
In addition to the canonical B-form structure, DNA can adopt alternative conformations including Z DNA, triplex DNA, as well as G4 and i-Motif quadruplex structures. Such structures have been shown to form in cells in a dynamic manner. Monoclonal antibodies against such structures represent key tools to study the biological functions of these structures. Here we provide protocols for the generation of antibody fragments against structured DNA using phage display selections.
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157
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Sun Y, Ji Y, Wang D, Wang J, Liu D. Stabilization of an intermolecular i-motif by lipid modification of cytosine-oligodeoxynucleotides. Org Biomol Chem 2019; 16:4857-4863. [PMID: 29926887 DOI: 10.1039/c8ob00920a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This paper describes the stabilization of an intermolecular i-motif by lipophilic modification on the 3'-terminus of oligonucleotides. The hydrophobic aliphatic chain connected at the 3'-terminus of a trinucleotide (dC)3 promoted the formation of an i-motif and significantly enhanced the quadruplex's stability. The impact of lipophilic modification on i-motif's thermal stability was studied by UV-thermal denaturation melting experiments and isothermal titration calorimetry. We found that alkyl chains containing more than 14 carbon atoms could elevate the i-motif structure's stability in a wide range of pH and concentrations.
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Affiliation(s)
- Yawei Sun
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (Huadong), Qingdao, 258000, China.
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158
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Fleming AM, Stewart KM, Eyring GM, Ball TE, Burrows CJ. Unraveling the 4n - 1 rule for DNA i-motif stability: base pairs vs. loop lengths. Org Biomol Chem 2019; 16:4537-4546. [PMID: 29873385 DOI: 10.1039/c8ob01198b] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Previously our laboratory identified that poly-2'-deoxycytidine (dCn) strands of DNA with lengths greater than 12 nucleotides could adopt i-motif folds, while the pH-dependent stabilities follow a 4n - 1 repeat pattern with respect to chain length (J. Am. Chem. Soc., 2017, 139, 4682-4689). Herein, model i-motif folds in which loop configurations were forced by judiciously mutating dC to non-dC nucleotides allowed a structural model to be proposed to address this phenomenon. The model was developed by systematically studying two i-motifs with either an even or odd number of d(C·C)+ hemiprotonated base pairs in the core. First, a trend in the pH-dependent stability vs. loop nucleotide identity was observed: dC > dT ∼ dU ≫ dA ∼ dG. Next, loops comprised of dT nucleotides in the two different core base pair configurations were studied while systematically changing the loop lengths. We found that an i-motif with an even number of base pairs in the core with a single nucleotide in each of the three loops was the most stable, as well as an i-motif with an odd number of core base pairs having one nucleotide in the two exterior loops and three nucleotides in the central loop. A systematic increase in the central loop from 1-4 nucleotides for an odd number of base pairs in the i-motif core reproduced the 4n - 1 repeat pattern observed in the poly-dCn strands. Additional loop configurations were studied to further support the model. The results are discussed with respect to their biological relevance.
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Affiliation(s)
- Aaron M Fleming
- Department of Chemistry, 315 S. 1400 East. and University of Utah, Salt Lake City, UT 84112-0850, USA.
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159
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Wang Y, Dong Z, Hu H, Yang Q, Hou X, Wu P. DNA-modulated photosensitization: current status and future aspects in biosensing and environmental monitoring. Anal Bioanal Chem 2019; 411:4415-4423. [PMID: 30734855 DOI: 10.1007/s00216-019-01605-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/22/2018] [Accepted: 01/11/2019] [Indexed: 01/22/2023]
Abstract
Recently, photosensitized oxidation has been explored in many fields of research and applications, such as photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT). Although the photosensitized generation of ROS features emerging applications, controllable management of the photosensitization process is still sometimes problematic. DNA has long been considered the carrier for genetic information. With the in-depth study of the chemical properties of DNA, the molecular function of DNA is gradually witnessed by the scientific community. Undoubtedly, the selective recognition nature of DNA endows them excellent candidate modulators for photosensitized oxidation. According to current research, reports on DNA regulation of photosensitized oxidation can be roughly divided into two categories in principle: P-Q quenching pair-switched photosensitization and host-guest interaction-switched photosensitization. In this review, the development status of these two analytical methods will be summarized, and the future development direction of DNA-modulated photosensitization in biosensing and environmental monitoring will also be prospected.
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Affiliation(s)
- Yanying Wang
- College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Zhen Dong
- College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Hao Hu
- Analytical & Testing Center, Sichuan University, Chengdu, 610064, China
| | - Qing Yang
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, China.
| | - Xiandeng Hou
- College of Chemistry, Sichuan University, Chengdu, 610064, China.,Analytical & Testing Center, Sichuan University, Chengdu, 610064, China
| | - Peng Wu
- College of Chemistry, Sichuan University, Chengdu, 610064, China. .,Analytical & Testing Center, Sichuan University, Chengdu, 610064, China. .,State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, China.
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160
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Aksenova AY, Mirkin SM. At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences. Genes (Basel) 2019; 10:genes10020118. [PMID: 30764567 PMCID: PMC6410037 DOI: 10.3390/genes10020118] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023] Open
Abstract
Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.
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Affiliation(s)
- Anna Y Aksenova
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia.
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02421, USA.
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161
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pH-driven conformational switch between non-canonical DNA structures in a C-rich domain of EGFR promoter. Sci Rep 2019; 9:1210. [PMID: 30718769 PMCID: PMC6362134 DOI: 10.1038/s41598-018-37968-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/17/2018] [Indexed: 01/10/2023] Open
Abstract
EGFR is an oncogene that encodes for a trans-membrane tyrosine kinase receptor. Its mis-regulation is associated to several human cancers that, consistently, can be treated by selective tyrosine kinase inhibitors. The proximal promoter of EGFR contains a G-rich domain located at 272 bases upstream the transcription start site. We previously proved it folds into two main interchanging G-quadruplex structures, one of parallel and one of hybrid topology. Here we present the first evidences supporting the ability of the complementary C-rich strand (EGFR-272_C) to assume an intramolecular i-Motif (iM) structure that, according to the experimental conditions (pH, presence of co-solvent and salts), can coexist with a different arrangement we referred to as a hairpin. The herein identified iM efficiently competes with the canonical pairing of the two complementary strands, indicating it as a potential novel target for anticancer therapies. A preliminary screening for potential binders identified some phenanthroline derivatives as able to target EGFR-272_C at multiple binding sites when it is folded into an iM.
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162
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Sabale PM, Tanpure AA, Srivatsan SG. Probing the competition between duplex and G-quadruplex/i-motif structures using a conformation-sensitive fluorescent nucleoside probe. Org Biomol Chem 2019; 16:4141-4150. [PMID: 29781489 PMCID: PMC6086326 DOI: 10.1039/c8ob00646f] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Double-stranded segments of a genome that can potentially form G-quadruplex (GQ) and/or i-motif (iM) structures are considered to be important regulatory elements. Hence, the development of a common probe that can detect GQ and iM structures and also distinguish them from a duplex structure will be highly useful in understanding the propensity of such segments to adopt duplex or non-canonical four-stranded structures. Here, we describe the utility of a conformation-sensitive fluorescent nucleoside analog, which was originally developed as a GQ sensor, in detecting the iM structures of C-rich DNA oligonucleotides (ONs). The analog is based on a 5-(benzofuran-2-yl)uracil scaffold, which when incorporated into C-rich ONs (e.g., telomeric repeats) fluorescently distinguishes an iM from random coil and duplex structures. Steady-state and time-resolved fluorescence techniques enabled the determination of transition pH for the transformation of a random coil to an iM structure. Furthermore, a qualitative understanding on the relative population of duplex and GQ/iM forms under physiological conditions could be gained by correlating the fluorescence, CD and thermal melting data. Taken together, this sensor could provide a general platform to profile double-stranded promoter regions in terms of their ability to adopt four-stranded structures, and also could support approaches to discover functional GQ and iM binders.
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Affiliation(s)
- Pramod M Sabale
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India.
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163
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Saranathan N, Vivekanandan P. G-Quadruplexes: More Than Just a Kink in Microbial Genomes. Trends Microbiol 2019; 27:148-163. [PMID: 30224157 PMCID: PMC7127049 DOI: 10.1016/j.tim.2018.08.011] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/17/2018] [Accepted: 08/24/2018] [Indexed: 02/06/2023]
Abstract
G-quadruplexes (G4s) are noncanonical nucleic acid secondary structures formed by guanine-rich DNA and RNA sequences. In this review we aim to provide an overview of the biological roles of G4s in microbial genomes with emphasis on recent discoveries. G4s are enriched and conserved in the regulatory regions of microbes, including bacteria, fungi, and viruses. Importantly, G4s in hepatitis B virus (HBV) and hepatitis C virus (HCV) genomes modulate genes crucial for virus replication. Recent studies on Epstein-Barr virus (EBV) shed light on the role of G4s within the microbial transcripts as cis-acting regulatory signals that modulate translation and facilitate immune evasion. Furthermore, G4s in microbial genomes have been linked to radioresistance, antigenic variation, recombination, and latency. G4s in microbial genomes represent novel therapeutic targets for antimicrobial therapy.
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Affiliation(s)
- Nandhini Saranathan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Perumal Vivekanandan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India.
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164
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Debnath M, Fatma K, Dash J. Chemical Regulation of DNA i‐Motifs for Nanobiotechnology and Therapeutics. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201813288] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Manish Debnath
- School of Chemical SciencesIndian Association for the Cultivation of Science Jadavpur Kolkata- 700032 India
| | - Khushnood Fatma
- School of Chemical SciencesIndian Association for the Cultivation of Science Jadavpur Kolkata- 700032 India
| | - Jyotirmayee Dash
- School of Chemical SciencesIndian Association for the Cultivation of Science Jadavpur Kolkata- 700032 India
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165
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Debnath M, Fatma K, Dash J. Chemical Regulation of DNA i-Motifs for Nanobiotechnology and Therapeutics. Angew Chem Int Ed Engl 2019; 58:2942-2957. [PMID: 30600876 DOI: 10.1002/anie.201813288] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/27/2018] [Indexed: 12/20/2022]
Abstract
DNA sequences rich in cytosine have the propensity, under acidic pH, to fold into four-stranded intercalated DNA structures called i-motifs. Recent studies have provided significant breakthroughs that demonstrate how chemists can manipulate these structures for nanobiotechnology and therapeutics. The first section of this Minireview discusses the development of advanced functional nanostructures by synthetic conjugation of i-motifs with organic scaffolds and metal nanoparticles and their role in therapeutics. The second section highlights the therapeutic targeting of i-motifs with chemical scaffolds and their significance in biology. For this, first we shed light on the long-lasting debate regarding the stability of i-motifs under physiological conditions. Next, we present a comparative analysis of recently reported small molecules for specifically targeting i-motifs over other abundant DNA structures and modulating their function in cellular systems. These advances provide new insights into i-motif-targeted regulation of gene expression, telomere maintenance, and therapeutic applications.
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Affiliation(s)
- Manish Debnath
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-, 700032, India
| | - Khushnood Fatma
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-, 700032, India
| | - Jyotirmayee Dash
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-, 700032, India
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166
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Zuffo M, Xie X, Granzhan A. Strength in Numbers: Development of a Fluorescence Sensor Array for Secondary Structures of DNA. Chemistry 2019; 25:1812-1818. [DOI: 10.1002/chem.201805422] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Michela Zuffo
- CNRS UMR9187; INSERM U1196; Institut Curie; PSL Research University; 91405 Orsay France
- CNRS UMR9187; INSERM U1196; Université Paris Sud; Université Paris Saclay; 91405 Orsay France
| | - Xiao Xie
- CNRS UMR9187; INSERM U1196; Institut Curie; PSL Research University; 91405 Orsay France
- CNRS UMR9187; INSERM U1196; Université Paris Sud; Université Paris Saclay; 91405 Orsay France
| | - Anton Granzhan
- CNRS UMR9187; INSERM U1196; Institut Curie; PSL Research University; 91405 Orsay France
- CNRS UMR9187; INSERM U1196; Université Paris Sud; Université Paris Saclay; 91405 Orsay France
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167
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Nuthanakanti A. Cytidine and ribothymidine nucleolipids synthesis, organogelation, and selective anion and metal ion responsiveness. NEW J CHEM 2019. [DOI: 10.1039/c9nj03276b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nucleolipids of 2′,3′-O-diacylatedribothymidine supports the organogelation by utilizing inherent self-base pairing and solvent mediated bifurcated H-bonding and hydrophobic effect. These organogels exhibits unusual Hg2+ mediated base pairing.
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Affiliation(s)
- Ashok Nuthanakanti
- Department of Chemistry
- Indian Institute of Science Education and Research (IISER) Pune
- Pune 411008
- India
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168
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Satpathi S, Sappati S, Das K, Hazra P. Structural characteristics requisite for the ligand-based selective detection of i-motif DNA. Org Biomol Chem 2019; 17:5392-5399. [DOI: 10.1039/c9ob01020c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A new approach has been explored to detect i-motif DNA structures over its complementary GQ DNA based on the hemi-protonated cytosine–cytosine (C+–C) base pairing recognition. This approach also shows its versatility by detecting various i-motif DNA structures with different chain lengths, molecularity and sizes, etc.
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Affiliation(s)
- Sagar Satpathi
- Department of Chemistry
- Indian Institute of Science Education and Research (IISER)
- Pune
- India
| | - Subrahmanyam Sappati
- Department of Chemistry
- Indian Institute of Science Education and Research (IISER)
- Pune
- India
| | - Konoya Das
- Department of Chemistry
- Indian Institute of Science Education and Research (IISER)
- Pune
- India
| | - Partha Hazra
- Department of Chemistry
- Indian Institute of Science Education and Research (IISER)
- Pune
- India
- Centre for Energy Science
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169
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Wolski P, Nieszporek K, Panczyk T. G-Quadruplex and I-Motif Structures within the Telomeric DNA Duplex. A Molecular Dynamics Analysis of Protonation States as Factors Affecting Their Stability. J Phys Chem B 2018; 123:468-479. [DOI: 10.1021/acs.jpcb.8b11547] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pawel Wolski
- Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30239 Cracow, Poland
| | - Krzysztof Nieszporek
- Department of Chemistry, Maria Curie-Sklodowska University, pl. M. Curie-Sklodowskiej 3, 20031 Lublin, Poland
| | - Tomasz Panczyk
- Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30239 Cracow, Poland
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170
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Ge Z, Gu H, Li Q, Fan C. Concept and Development of Framework Nucleic Acids. J Am Chem Soc 2018; 140:17808-17819. [PMID: 30516961 DOI: 10.1021/jacs.8b10529] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Zhilei Ge
- School of Chemistry and Chemical Engineering, and Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hongzhou Gu
- Center for Biotechnology and Biomedical Engineering, Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Qian Li
- School of Chemistry and Chemical Engineering, and Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, and Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
- Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
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171
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Park JJ, Lee CS, Han SY. Proton Transfer Accounting for Anomalous Collision-Induced Dissociation of Proton-Bound Hoogsteen Base Pair of Cytosine and Guanine. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2368-2379. [PMID: 30215166 DOI: 10.1007/s13361-018-2060-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/08/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
To understand the anomalous collision-induced dissociation (CID) behavior of the proton-bound Hoogsteen base pair of cytosine (C) and guanine (G), C:H+∙∙∙G, we investigated CID of a homologue series of proton-bound heterodimers of C, 1-methylcytosine, and 5-methylcytosine with G as a common base partner. The CID experiments were performed in an energy-resolved way (ER-CID) under both multiple and near-single collision conditions. The relative stabilities of the protonated complexes examined by ER-CID suggested that the proton-bound complexes produced by electrospray ionization in this study are proton-bound Hoogsteen base pairs. On the other hand, in contrast to the other base pairs, CID of C:H+∙∙∙G exhibited more abundant productions of C:H+, the fragment protonated on the moiety with a smaller proton affinity, than that of G:H+. This appeared to contradict general prediction based on the kinetic method. However, further theoretical exploration of potential energy surfaces found that there can be facile proton transfers in the proton-bound Hoogsteen base pairs during the CID process, which makes the process accessible to an additional product state of O-protonated C for C:H+ fragments. The presence of an additional dissociation channel, which in other words corresponds to twofold degeneracy in the transition state leading to C:H+ fragments, effectively doubles the apparent reaction rate for production of C:H+. In this way, the process gives rise to the anomaly, the observed pronounced formation of C:H+ in the CID of the proton-bound Hoogsteen base pair, C:H+∙∙∙G. Graphical Abstract ᅟ.
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Affiliation(s)
- Jeong Ju Park
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Choong Sik Lee
- Scientific Investigation Laboratory, Ministry of National Defense, 22 Itaewon-ro, Yongsan-gu, Seoul, 04383, Republic of Korea
| | - Sang Yun Han
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.
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172
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Journey SN, Alden SL, Hewitt WM, Peach ML, Nicklaus MC, Schneekloth JS. Probing the hras-1 Y i-motif with small molecules. MEDCHEMCOMM 2018; 9:2000-2007. [PMID: 30647878 PMCID: PMC6301200 DOI: 10.1039/c8md00311d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/19/2018] [Indexed: 01/21/2023]
Abstract
Non-B DNA structures represent intriguing and challenging targets for small molecules. For example, the promoter of the HRAS oncogene contains multiple G-quadruplex and i-motif structures, atypical globular folds that serve as molecular switches for gene expression. Of the two, i-motif structures are far less studied. Here, we report the first example of small organic compounds that directly interact with the hras-1Y i-motif. We use a small molecule microarray screen to identify drug-like small molecules that bind to the hras-1Y i-motif but not to several other DNA or RNA secondary structures. Two different lead compounds, 1 and 2, were discovered to have 7.4 ± 5.3 μM and 5.9 ± 3.7 μM binding affinity by surface plasmon resonance and similar affinity by fluorescence titration. A structure-activity relationship (SAR) was developed and two improved analogues of 2 demonstrated submicromolar binding affinities. Both compounds display pH-dependent binding, indicating that they interact with the DNA only when the i-motif is properly folded. Chemical shift perturbation shows that 1 alters the structure of the i-motif, while 2 has no effect on the i-motif conformation, indicating different modes of interaction.
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Affiliation(s)
- Sara N Journey
- Chemical Biology Laboratory , National Cancer Institute , Frederick , MD , USA .
| | - Stephanie L Alden
- Chemical Biology Laboratory , National Cancer Institute , Frederick , MD , USA .
| | - Will M Hewitt
- Chemical Biology Laboratory , National Cancer Institute , Frederick , MD , USA .
| | - Megan L Peach
- Chemical Biology Laboratory , Basic Science Program , Frederick National Laboratory for Cancer Research , Leidos Biomedical Research Inc. , Frederick , MD , USA
| | - Marc C Nicklaus
- Chemical Biology Laboratory , National Cancer Institute , Frederick , MD , USA .
| | - John S Schneekloth
- Chemical Biology Laboratory , National Cancer Institute , Frederick , MD , USA .
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173
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Sedghi Masoud S, Nagasawa K. i-Motif-Binding Ligands and Their Effects on the Structure and Biological Functions of i-Motif. Chem Pharm Bull (Tokyo) 2018; 66:1091-1103. [DOI: 10.1248/cpb.c18-00720] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Shadi Sedghi Masoud
- Department of Life Science and Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology
| | - Kazuo Nagasawa
- Department of Life Science and Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology
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174
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Zarudnaya MI, Kolomiets IM, Potyahaylo AL, Hovorun DM. Structural transitions in poly(A), poly(C), poly(U), and poly(G) and their possible biological roles. J Biomol Struct Dyn 2018; 37:2837-2866. [PMID: 30052138 DOI: 10.1080/07391102.2018.1503972] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The homopolynucleotide (homo-oligonucleotide) tracts function as regulatory elements at various stages of mRNAs life cycle. Numerous cellular proteins specifically bind to these tracts. Among them are the different poly(A)-binding proteins, poly(C)-binding proteins, multifunctional fragile X mental retardation protein which binds specifically both to poly(G) and poly(U) and others. Molecular mechanisms of regulation of gene expression mediated by homopolynucleotide tracts in RNAs are not fully understood and the structural diversity of these tracts can contribute substantially to this regulation. This review summarizes current knowledge on different forms of homoribopolynucleotides, in particular, neutral and acidic forms of poly(A) and poly(C), and also biological relevance of homoribopolynucleotide (homoribo-oligonucleotide) tracts is discussed. Under physiological conditions, the acidic forms of poly(A) and poly(C) can be induced by proton transfer from acidic amino acids of proteins to adenine and cytosine bases. Finally, we present potential mechanisms for the regulation of some biological processes through the formation of intramolecular poly(A) duplexes.
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Affiliation(s)
- Margarita I Zarudnaya
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Iryna M Kolomiets
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Andriy L Potyahaylo
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Dmytro M Hovorun
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine.,b Department of Molecular Biotechnology and Bioinformatics , Institute of High Technologies, Taras Shevchenko National University of Kyiv , Kyiv , Ukraine
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175
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Chu B, Zhang D, Hwang W, Paukstelis PJ. Crystal Structure of a Tetrameric DNA Fold-Back Quadruplex. J Am Chem Soc 2018; 140:16291-16298. [PMID: 30384604 DOI: 10.1021/jacs.8b10153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
DNA can adopt many structures beyond the Watson-Crick duplex. However, the bounds of DNA structural diversity and how these structures might regulate biological processes is only beginning to be understood. Here, we describe the 1.05 Å resolution crystal structure of a DNA oligonucleotide that self-associates to form a non-G-quadruplex fold-back structure. Distinct from previously described fold-back quadruplexes, two-fold-back dimers interact through noncanonical and Watson-Crick interactions to form a tetrameric assembly. These interactions include a hexad base pairing arrangement from two C-G-G base triples. The assembly is dependent on divalent cations, and the interface between the dimeric units creates a cavity in which a cation resides. This structure provides new sequence and structural contexts for the formation of fold-back quadruplexes, further highlighting the potential biological importance of this type of noncanonical DNA structure. This structure may also serve as the basis for designing new types of DNA nanoarchitectures or cation sensors based on the strong divalent cation dependence.
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Affiliation(s)
- Betty Chu
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization , University of Maryland , College Park , Maryland 20742 , United States
| | - Daoning Zhang
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization , University of Maryland , College Park , Maryland 20742 , United States
| | - Wonseok Hwang
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization , University of Maryland , College Park , Maryland 20742 , United States
| | - Paul J Paukstelis
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization , University of Maryland , College Park , Maryland 20742 , United States
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176
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A Turn-On Detection of DNA Sequences by Means of Fluorescence of DNA-Templated Silver Nanoclusters via Unique Interactions of a Hydrated Ionic Liquid. Molecules 2018; 23:molecules23112889. [PMID: 30404141 PMCID: PMC6278258 DOI: 10.3390/molecules23112889] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/01/2018] [Accepted: 11/04/2018] [Indexed: 02/02/2023] Open
Abstract
Nucleic acid stability and structure, which are crucial to the properties of fluorescent DNA-templated silver nanoclusters (DNA-Ag NCs), significantly change in ionic liquids. In this work, our purpose was to study DNA-Ag NCs in a buffer containing the hydrated ionic liquid of choline dihydrogen phosphate (choline dhp) to improve fluorescence for application in DNA detection. Due to the stabilisation of an i-motif structure by the choline cation, a unique fluorescence emission—that was not seen in an aqueous buffer—was observed in choline dhp and remained stable for more than 30 days. A DNA-Ag NCs probe was designed to have greater fluorescence intensity in choline dhp in the presence of a target DNA. A turn-on sensing platform in choline dhp was built for the detection of the BRCA1 gene, which is related to familial breast and ovarian cancers. This platform showed better sensitivity and selectivity in distinguishing a target sequence from a mutant sequence in choline dhp than in the aqueous buffer. Our study provides new evidence regarding the effects of structure on properties of fluorescent DNA-Ag NCs and expands the applications of fluorescent DNA-Ag NCs in an ionic liquid because of improved sensitivity and selectivity.
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177
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Ding Y, Fleming AM, Burrows CJ. Case studies on potential G-quadruplex-forming sequences from the bacterial orders Deinococcales and Thermales derived from a survey of published genomes. Sci Rep 2018; 8:15679. [PMID: 30356061 PMCID: PMC6200779 DOI: 10.1038/s41598-018-33944-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/06/2018] [Indexed: 12/13/2022] Open
Abstract
Genomes provide a platform for storage of chemical information that must be stable under the context in which an organism thrives. The 2'-deoxyguanosine (G) nucleotide has the potential to provide additional chemical information beyond its Watson-Crick base-pairing capacity. Sequences with four or more runs of three G nucleotides each are potential G-quadruplex forming sequences (PQSs) that can adopt G-quadruplex folds. Herein, we analyzed sequenced genomes from the NCBI database to determine the PQS densities of the genome sequences. First, we found organisms with large genomes, including humans, alligators, and maize, have similar densities of PQSs (~300 PQSs/Mbp), and the genomes are significantly enriched in PQSs with more than four G tracks. Analysis of microorganism genomes found a greater diversity of PQS densities. In general, PQS densities positively tracked with the GC% of the genome. Exceptions to this observation were the genomes from thermophiles that had many more PQSs than expected by random chance. Analysis of the location of these PQSs in annotated genomes from the order Thermales showed these G-rich sequences to be randomly distributed; in contrast, in the order Deinococcales the PQSs were enriched and biased around transcription start sites of genes. Four representative PQSs, two each from the Thermales and Deinococcales, were studied by biophysical methods to establish the ability of them to fold to G-quadruplexes. The experiments found the two PQSs in the Thermales did not adopt G-quadruplex folds, while the two most common in the Deinococcales adopted stable parallel-stranded G-quadruplexes. The findings lead to a hypothesis that thermophilic organisms are enriched with PQSs as an unavoidable consequence to stabilize thermally their genomes to live at high temperature; in contrast, the genomes from stress-resistant bacteria found in the Deinococcales may utilize PQSs for gene regulatory purposes.
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Affiliation(s)
- Yun Ding
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT, 84112-0850, United States.
| | - Aaron M Fleming
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT, 84112-0850, United States
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT, 84112-0850, United States.
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178
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Abdelhamid MAS, Gates AJ, Waller ZAE. Destabilization of i-Motif DNA at Neutral pH by G-Quadruplex Ligands. Biochemistry 2018; 58:245-249. [PMID: 30350580 DOI: 10.1021/acs.biochem.8b00968] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Numerous studies have been published stressing the importance of finding ligands that can bind specifically to DNA secondary structures. Several have identified ligands that are presented as having specific binding to the G-quadruplex; however, these were not originally tested on the complementary i-motif structure. The i-motif was overlooked and presumed to be irrelevant due to the belief that the hemiprotonated (cytosine+-cytosine) base pair at the core of the structure required acidic pH. The pathophysiological relevance of i-motifs has since been documented, as well as the discovery of several genomic sequences, which can form i-motif at neutral pH. Using different biophysical methodologies, we provide experimental evidence to show that widely used G-quadruplex ligands interact with i-motif structures at neutral pH, generally leading to their destabilization. Crucially, this has implications both for the search for quadruplex binding compounds as well as for the effects of compounds reported to have G-quadruplex specificity without examining their effects on i-motif.
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Affiliation(s)
- Mahmoud A S Abdelhamid
- School of Pharmacy , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , United Kingdom.,Centre for Molecular and Structural Biochemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , United Kingdom
| | - Andrew J Gates
- Centre for Molecular and Structural Biochemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , United Kingdom.,School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , United Kingdom
| | - Zoë A E Waller
- School of Pharmacy , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , United Kingdom.,Centre for Molecular and Structural Biochemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , United Kingdom
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179
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Sedghi Masoud S, Yamaoki Y, Ma Y, Marchand A, Winnerdy FR, Gabelica V, Phan AT, Katahira M, Nagasawa K. Analysis of Interactions between Telomeric i-Motif DNA and a Cyclic Tetraoxazole Compound. Chembiochem 2018; 19:2268-2272. [PMID: 30160816 DOI: 10.1002/cbic.201800425] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Indexed: 12/31/2022]
Abstract
The interaction of a macrocyclic tetraoxazole compound, L2H2-4OTD (1), with two aminoalkyl side chains and telomeric i-motif, was investigated by means of electrophoretic mobility shift assay, circular dichroism spectroscopy, mass spectrometry and NMR spectroscopy analyses. The results indicate that 1 interacts with the i-motif structure at two preferred binding sites.
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Affiliation(s)
- Shadi Sedghi Masoud
- Department of Life Science and Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588, Japan
| | - Yudai Yamaoki
- Institute of Advanced Energy, Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Yue Ma
- Department of Life Science and Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588, Japan
| | - Adrien Marchand
- Université de Bordeaux, INSERM, CNRS, Acides Nucléiques, Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 2 rue Robert Escarpit, 33607, Pessac, France
| | - Fernaldo Richtia Winnerdy
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, SPMS PAP 05-04, 637371, Singapore, Singapore
| | - Valérie Gabelica
- Université de Bordeaux, INSERM, CNRS, Acides Nucléiques, Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 2 rue Robert Escarpit, 33607, Pessac, France
| | - Anh Tuân Phan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, SPMS PAP 05-04, 637371, Singapore, Singapore
| | - Masato Katahira
- Institute of Advanced Energy, Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Kazuo Nagasawa
- Department of Life Science and Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588, Japan
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180
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Li L, Jiang Y, Cui C, Yang Y, Zhang P, Stewart K, Pan X, Li X, Yang L, Qiu L, Tan W. Modulating Aptamer Specificity with pH-Responsive DNA Bonds. J Am Chem Soc 2018; 140:13335-13339. [PMID: 30212189 DOI: 10.1021/jacs.8b08047] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Aptamers that recognize specific cells in a complex environment have emerged as invaluable molecular tools in bioanalysis and in the development of targeted therapeutics. The selective recognition of aptamers, however, can be compromised by the coexistence of target receptors on both target cells and other cells. To address this problem, we constructed a structure-switchable aptamer (SW-Apt) with reconfigurable binding affinity in accordance with the microenvironment of target cells. The SW-Apt makes use of i-motifs, which are quadruplex structures that form in sequences rich in cytosine. More specifically, we report the design of single-stranded, pH-responsive i-motif-modified aptamers able to bind specifically with target cells by exploiting their pH. Here, the i-motif serves as a structural domain to either facilitate the binding ability of aptamers to target cells or suppress the binding ability of aptamers to nontarget cell based on the pH of the cellular microenvironment. SW-Apt exhibited high binding ability with target cells at acidic pH, while no obvious binding was observed at physiological pH. The i-motif-induced structure-switching was verified with Förster resonance energy transfer and circular dichroism spectroscopy. Notably, SW-Apt exhibits high specificity in serum and excellent stability, likely attributed to the folded quadruplex i-motif structure. This study provides a simple and efficient strategy to chemically modulate aptamer binding ability and thus improve aptamer binding specificity to target cells, irrespective of the coexistence of identical receptors on target and nontarget cells.
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Affiliation(s)
- Long Li
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States
| | - Ying Jiang
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States.,Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Aptamer Engineering Center of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Cheng Cui
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Aptamer Engineering Center of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Yu Yang
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States.,Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai 200240 , P. R. China
| | - Penghui Zhang
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States
| | - Kimberly Stewart
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States
| | - Xiaoshu Pan
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States
| | - Xiaowei Li
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States
| | - Lu Yang
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States
| | - Liping Qiu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Aptamer Engineering Center of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Weihong Tan
- Department of Chemistry and Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute , University of Florida , Gainesville , Florida 32611-7200 , United States.,Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Aptamer Engineering Center of Hunan Province , Hunan University , Changsha 410082 , P. R. China.,Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai 200240 , P. R. China
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181
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Shakya A, King JT. DNA Local-Flexibility-Dependent Assembly of Phase-Separated Liquid Droplets. Biophys J 2018; 115:1840-1847. [PMID: 30342746 PMCID: PMC6303412 DOI: 10.1016/j.bpj.2018.09.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 12/18/2022] Open
Abstract
Phase separation of intracellular components has been recently realized as a mechanism by which cells achieve membraneless organization. Here, we study the associative liquid-liquid phase separation (LLPS) of DNA upon complexation with cationic polypeptides. Comparing the phase behavior of different single-stranded DNA as well as double-stranded DNA (dsDNA) sequences that differ in persistence lengths, we find that DNA local flexibility, not simply charge density, determines the LLPS. Furthermore, in a nucleotide- and DNA-dependent manner, free nucleotide triphosphates promote LLPS of polypeptide-dsDNA complexes that are otherwise prone to precipitation. Under these conditions, dsDNA undergoes a secondary phase separation forming liquid-crystalline subcompartments inside the droplets. These results point toward a role of local DNA flexibility, encoded in the sequence, in the regulation and selectivity of multicomponent LLPS in membraneless intracellular organization.
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Affiliation(s)
- Anisha Shakya
- Institute for Basic Science, Center for Soft and Living Matter, Ulsan, Republic of Korea
| | - John T King
- Institute for Basic Science, Center for Soft and Living Matter, Ulsan, Republic of Korea.
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182
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Masai H, Kakusho N, Fukatsu R, Ma Y, Iida K, Kanoh Y, Nagasawa K. Molecular architecture of G-quadruplex structures generated on duplex Rif1-binding sequences. J Biol Chem 2018; 293:17033-17049. [PMID: 30217821 DOI: 10.1074/jbc.ra118.005240] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/06/2018] [Indexed: 01/07/2023] Open
Abstract
G-quadruplexes (G4s) are four-stranded DNA structures comprising stacks of four guanines, are prevalent in genomes, and have diverse biological functions in various chromosomal structures. A conserved protein, Rap1-interacting factor 1 (Rif1) from fission yeast (Schizosaccharomyces pombe), binds to Rif1-binding sequence (Rif1BS) and regulates DNA replication timing. Rif1BS is characterized by the presence of multiple G-tracts, often on both strands, and their unusual spacing. Although previous studies have suggested generation of G4-like structures on duplex Rif1BS, its precise molecular architecture remains unknown. Using gel-shift DNA binding assays and DNA footprinting with various nuclease probes, we show here that both of the Rif1BS strands adopt specific higher-order structures upon heat denaturation. We observed that the structure generated on the G-strand is consistent with a G4 having unusually long loop segments and that the structure on the complementary C-strand does not have an intercalated motif (i-motif). Instead, we found that the formation of the C-strand structure depends on the G4 formation on the G-strand. Thus, the higher-order structure generated at Rif1BS involved both DNA strands, and in some cases, G4s may form on both of these strands. The presence of multiple G-tracts permitted the formation of alternative structures when some G-tracts were mutated or disrupted by deazaguanine replacement, indicating the robust nature of DNA higher-order structures generated at Rif1BS. Our results provide general insights into DNA structures generated at G4-forming sequences on duplex DNA.
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Affiliation(s)
- Hisao Masai
- From the Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan,
| | - Naoko Kakusho
- From the Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Rino Fukatsu
- From the Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Yue Ma
- the Department of Biotechnology and Life Science, Faculty of Technology, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan, and
| | - Keisuke Iida
- the Molecular Chirality Research Center, Synthetic Organic Chemistry, Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Yutaka Kanoh
- From the Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Kazuo Nagasawa
- the Department of Biotechnology and Life Science, Faculty of Technology, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan, and
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183
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Rogers RA, Fleming AM, Burrows CJ. Rapid Screen of Potential i-Motif Forming Sequences in DNA Repair Gene Promoters. ACS OMEGA 2018; 3:9630-9635. [PMID: 30198001 PMCID: PMC6120732 DOI: 10.1021/acsomega.8b01551] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
We have studied the in vitro stability of 25 potential i-motif-forming DNA sequences found within the promoter regions of 18 different human DNA repair genes. Three widely available methods of characterization were used to rapidly assess i-motif folding and stability and comprise a simple screen for preliminary identification of physiologically relevant i-motif forming sequences. Four highly pH-stable candidate sequences were identified exhibiting pH transitions (pH at which 50% of the oligodeoxynucleotides in solution are folded) at or above pH 6.6, thermal melting temperatures above 37 °C and isothermal UV difference spectra characteristic of 2'-deoxycytidine imino-nitrogen protonation. These newly identified i-motif forming sequences could represent novel targets for understanding and modulating human DNA repair gene expression.
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184
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Shiu SCC, Kinghorn AB, Sakai Y, Cheung YW, Heddle JG, Tanner JA. The Three S's for Aptamer-Mediated Control of DNA Nanostructure Dynamics: Shape, Self-Complementarity, and Spatial Flexibility. Chembiochem 2018; 19:1900-1906. [PMID: 30007003 DOI: 10.1002/cbic.201800308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Indexed: 01/11/2023]
Abstract
DNA aptamers are ideal tools to enable modular control of the dynamics of DNA nanostructures. For molecular recognition, they have a particular advantage over antibodies in that they can be integrated into DNA nanostructures in a bespoke manner by base pairing or nucleotide extension without any complex bioconjugation strategy. Such simplicity will be critical upon considering advanced therapeutic and diagnostic applications of DNA nanostructures. However, optimizing DNA aptamers for functional control of the dynamics of DNA nanostructure can be challenging. Herein, we present three considerations-shape, self-complementarity, and spatial flexibility-that should be paramount upon optimizing aptamer functionality. These lessons, learnt from the growing number of aptamer-nanostructure reports thus far, will be helpful for future studies in which aptamers are used to control the dynamics of nucleic acid nanostructures.
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Affiliation(s)
- Simon Chi-Chin Shiu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Andrew B Kinghorn
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Yusuke Sakai
- Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland
| | - Yee-Wai Cheung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Jonathan G Heddle
- Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland
| | - Julian A Tanner
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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185
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Benabou S, Ruckebusch C, Sliwa M, Aviñó A, Eritja R, Gargallo R, de Juan A. Study of light-induced formation of photodimers in the i-motif nucleic acid structure by rapid-scan FTIR difference spectroscopy and hybrid hard- and soft-modelling. Phys Chem Chem Phys 2018; 20:19635-19646. [PMID: 30010680 DOI: 10.1039/c8cp00850g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The i-motif is a DNA structure formed by cytosine-rich sequences, very relevant from a biochemical point of view and potentially useful in nanotechnology as pH-sensitive nanodevices or nanomotors. To provide a different view on the structural changes and dynamics of direct excitation processes involving i-motif structures, the use of rapid-scan FTIR spectroscopy is proposed. Hybrid hard- and soft-modelling based on the Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) algorithm has been used for the resolution of rapid-scan FTIR spectra and the interpretation of the photochemically induced time-dependent conformational changes of i-motif structures. The hybrid hard- and soft-modelling version of MCR-ALS (HS-MCR), which allows the introduction of kinetic models to describe process behavior, provides also rate constants associated with the transitions modeled. The results show that UV irradiation does not produce degradation of the studied sequences but induces the formation of photodimers. The presence of these affect much more the stability of i-motif structures formed by short sequences than that of those formed by longer sequences containing additional structural stabilizing elements, such as hairpins.
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Affiliation(s)
- Sanae Benabou
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí I Franquès 1-11, E-08028 Barcelona, Spain.
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186
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Pagano A, Iaccarino N, Abdelhamid MAS, Brancaccio D, Garzarella EU, Di Porzio A, Novellino E, Waller ZAE, Pagano B, Amato J, Randazzo A. Common G-Quadruplex Binding Agents Found to Interact With i-Motif-Forming DNA: Unexpected Multi-Target-Directed Compounds. Front Chem 2018; 6:281. [PMID: 30137743 PMCID: PMC6066642 DOI: 10.3389/fchem.2018.00281] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/22/2018] [Indexed: 11/26/2022] Open
Abstract
G-quadruplex (G4) and i-motif (iM) are four-stranded non-canonical nucleic acid structural arrangements. Recent evidences suggest that these DNA structures exist in living cells and could be involved in several cancer-related processes, thus representing an attractive target for anticancer drug discovery. Efforts toward the development of G4 targeting compounds have led to a number of effective bioactive ligands. Herein, employing several biophysical methodologies, we studied the ability of some well-known G4 ligands to interact with iM-forming DNA. The data showed that the investigated compounds are actually able to interact with both DNA in vitro, thus acting de facto as multi-target-directed agents. Interestingly, while all the compounds stabilize the G4, some of them significantly reduce the stability of the iM. The present study highlights the importance, when studying G4-targeting compounds, of evaluating also their behavior toward the i-motif counterpart.
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Affiliation(s)
- Alessia Pagano
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Nunzia Iaccarino
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Mahmoud A S Abdelhamid
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Diego Brancaccio
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | | | - Anna Di Porzio
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Ettore Novellino
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Zoë A E Waller
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, United Kingdom.,Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Bruno Pagano
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Jussara Amato
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Antonio Randazzo
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
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187
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Manna S, Srivatsan SG. Fluorescence-based tools to probe G-quadruplexes in cell-free and cellular environments. RSC Adv 2018; 8:25673-25694. [PMID: 30210793 PMCID: PMC6130854 DOI: 10.1039/c8ra03708f] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/08/2018] [Indexed: 12/26/2022] Open
Abstract
Biophysical and biochemical investigations provide compelling evidence connecting the four-stranded G-quadruplex (GQ) structure with its role in regulating multiple cellular processes. Hence, modulating the function of GQs by using small molecule binders is being actively pursued as a strategy to develop new chemotherapeutic agents. However, sequence diversity and structural polymorphism of GQs have posed immense challenges in terms of understanding what conformation a G-rich sequence adopts inside the cell and how to specifically target a GQ motif amidst several other GQ-forming sequences. In this context, here we review recent developments in the applications of biophysical tools that use fluorescence readout to probe the GQ structure and recognition in cell-free and cellular environments. First, we provide a detailed discussion on the utility of covalently labeled environment-sensitive fluorescent nucleoside analogs in assessing the subtle difference in GQ structures and their ligand binding abilities. Furthermore, a detailed discussion on structure-specific antibodies and small molecule probes used to visualize and confirm the existence of DNA and RNA GQs in cells is provided. We also highlight the open challenges in the study of tetraplexes (GQ and i-motif structures) and how addressing these challenges by developing new tools and techniques will have a profound impact on tetraplex-directed therapeutic strategies.
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Affiliation(s)
- Sudeshna Manna
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), PuneDr. Homi Bhabha RoadPune 411008India
| | - Seergazhi G. Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), PuneDr. Homi Bhabha RoadPune 411008India
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188
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Pont I, González-García J, Inclán M, Reynolds M, Delgado-Pinar E, Albelda MT, Vilar R, García-España E. Aza-Macrocyclic Triphenylamine Ligands for G-Quadruplex Recognition. Chemistry 2018; 24:10850-10858. [DOI: 10.1002/chem.201802077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/14/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Isabel Pont
- Department of Inorganic Chemistry, Institute of Molecular Science; University of Valencia; Catedrático José Beltran 2 46980 Paterna Spain
- Department of Chemistry; Imperial College London; London SW7 2AZ UK
| | - Jorge González-García
- Department of Inorganic Chemistry, Institute of Molecular Science; University of Valencia; Catedrático José Beltran 2 46980 Paterna Spain
- Department of Chemistry; Imperial College London; London SW7 2AZ UK
| | - Mario Inclán
- Department of Inorganic Chemistry, Institute of Molecular Science; University of Valencia; Catedrático José Beltran 2 46980 Paterna Spain
| | - Matthew Reynolds
- Department of Chemistry; Imperial College London; London SW7 2AZ UK
| | - Estefanía Delgado-Pinar
- Department of Inorganic Chemistry, Institute of Molecular Science; University of Valencia; Catedrático José Beltran 2 46980 Paterna Spain
| | - M. Teresa Albelda
- Department of Inorganic Chemistry, Institute of Molecular Science; University of Valencia; Catedrático José Beltran 2 46980 Paterna Spain
- GIBI2030, Grupo de Investigación Biomédica en Imagen, IIS La Fe; Valencia Spain
| | - Ramon Vilar
- Department of Chemistry; Imperial College London; London SW7 2AZ UK
| | - Enrique García-España
- Department of Inorganic Chemistry, Institute of Molecular Science; University of Valencia; Catedrático José Beltran 2 46980 Paterna Spain
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189
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Satpathi S, Das K, Hazra P. Silica nano-channel induced i-motif formation and stabilization at neutral and alkaline pH. Chem Commun (Camb) 2018; 54:7054-7057. [PMID: 29876546 DOI: 10.1039/c8cc02811g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Here, we have developed a new strategy to stabilize i-motif DNA in neutral and alkaline media by incorporating C-rich sequences inside silica nano-channels. Subsequently, the reversibility of this conformational transition has been achieved using a positively charged protein. Importantly, this entire conformational transition can be performed in multiple cycles, which offers an alternative way to control i-motif formation other than pH and thermal annealing.
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Affiliation(s)
- Sagar Satpathi
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune. Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
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190
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Molecular dynamics analysis of stabilities of the telomeric Watson-Crick duplex and the associated i-motif as a function of pH and temperature. Biophys Chem 2018; 237:22-30. [DOI: 10.1016/j.bpc.2018.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/30/2018] [Accepted: 03/30/2018] [Indexed: 11/19/2022]
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191
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Abstract
Advances in understanding mechanisms of nucleic acids have revolutionized molecular biology and medicine, but understanding of nontraditional nucleic acid conformations is less developed. The guanine quadruplex (G4) alternative DNA structure was first described in the 1960s, but the existence of G4 structures (G4-S) and their participation in myriads of biological functions are still underappreciated. Despite many tools to study G4s and many examples of roles for G4s in eukaryotic molecular processes and issues with uncontrolled G4-S formation, there is relatively little knowledge about the roles of G4-S in viral or prokaryotic systems. This review summarizes the state of the art with regard to G4-S in eukaryotes and their potential roles in human disease before discussing the evidence that G4-S have equivalent importance in affecting viral and bacterial life.
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Affiliation(s)
- H Steven Seifert
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA;
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192
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Morgan RK, Molnar MM, Batra H, Summerford B, Wadkins RM, Brooks TA. Effects of 5-Hydroxymethylcytosine Epigenetic Modification on the Stability and Molecular Recognition of VEGF i-Motif and G-Quadruplex Structures. J Nucleic Acids 2018; 2018:9281286. [PMID: 29862069 PMCID: PMC5976936 DOI: 10.1155/2018/9281286] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/31/2018] [Accepted: 04/03/2018] [Indexed: 12/14/2022] Open
Abstract
Promoters often contain asymmetric G- and C-rich strands, in which the cytosines are prone to epigenetic modification via methylation (5-mC) and 5-hydroxymethylation (5-hmC). These sequences can also form four-stranded G-quadruplex (G4) or i-motif (iM) secondary structures. Although the requisite sequences for epigenetic modulation and iM/G4 formation are similar and can overlap, they are unlikely to coexist. Despite 5-hmC being an oxidization product of 5-mC, the two modified bases cluster at distinct loci. This study focuses on the intersection of G4/iM formation and 5-hmC modification using the vascular endothelial growth factor (VEGF) gene promoter's CpG sites and examines whether incorporation of 5-hmC into iM/G4 structures had any physicochemical effect on formation, stability, or recognition by nucleolin or the cationic porphyrin, TMPyP4. No marked changes were found in the formation or stability of iM and G4 structures; however, changes in recognition by nucleolin or TMPyP4 occurred with 5-hmC modification wherein protein and compound binding to 5-hmC modified G4s was notably reduced. G4/iM structures in the VEGF promoter are promising therapeutic targets for antiangiogenic therapy, and this work contributes to a comprehensive understanding of their governing principles related to potential transcriptional control and targeting.
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Affiliation(s)
- Rhianna K. Morgan
- School of Pharmacy, Department of BioMolecular Sciences, Division of Pharmacology, University of Mississippi, University, MS 38677, USA
| | - Michael M. Molnar
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Harshul Batra
- School of Pharmacy, Department of BioMolecular Sciences, Division of Pharmacology, University of Mississippi, University, MS 38677, USA
| | - Bethany Summerford
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Randy M. Wadkins
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Tracy A. Brooks
- School of Pharmacy, Department of BioMolecular Sciences, Division of Pharmacology, University of Mississippi, University, MS 38677, USA
- School of Pharmacy and Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Binghamton University, Binghamton, NY 13902, USA
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193
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Kaulage MH, Bhattacharya S, Muniyappa K. Structural Characterization of i-Motif Structure in the Human Acetyl-CoA Carboxylase 1 Gene Promoters and Their Role in the Regulation of Gene Expression. Chembiochem 2018; 19:1078-1087. [DOI: 10.1002/cbic.201800021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Mangesh H. Kaulage
- Department of Biochemistry; Indian Institute of Science; Bengaluru 560012 India
- Department of Organic Chemistry; Indian Institute of Science; Bengaluru 560012 India
| | - Santanu Bhattacharya
- Department of Organic Chemistry; Indian Institute of Science; Bengaluru 560012 India
| | - K. Muniyappa
- Department of Biochemistry; Indian Institute of Science; Bengaluru 560012 India
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194
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I-motif DNA structures are formed in the nuclei of human cells. Nat Chem 2018; 10:631-637. [PMID: 29686376 DOI: 10.1038/s41557-018-0046-3] [Citation(s) in RCA: 350] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 03/14/2018] [Indexed: 12/25/2022]
Abstract
Human genome function is underpinned by the primary storage of genetic information in canonical B-form DNA, with a second layer of DNA structure providing regulatory control. I-motif structures are thought to form in cytosine-rich regions of the genome and to have regulatory functions; however, in vivo evidence for the existence of such structures has so far remained elusive. Here we report the generation and characterization of an antibody fragment (iMab) that recognizes i-motif structures with high selectivity and affinity, enabling the detection of i-motifs in the nuclei of human cells. We demonstrate that the in vivo formation of such structures is cell-cycle and pH dependent. Furthermore, we provide evidence that i-motif structures are formed in regulatory regions of the human genome, including promoters and telomeric regions. Our results support the notion that i-motif structures provide key regulatory roles in the genome.
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195
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Tsvetkov VB, Zatsepin TS, Belyaev ES, Kostyukevich YI, Shpakovski GV, Podgorsky VV, Pozmogova GE, Varizhuk AM, Aralov AV. i-Clamp phenoxazine for the fine tuning of DNA i-motif stability. Nucleic Acids Res 2018; 46:2751-2764. [PMID: 29474573 PMCID: PMC5888743 DOI: 10.1093/nar/gky121] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/01/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
Non-canonical DNA structures are widely used for regulation of gene expression, in DNA nanotechnology and for the development of new DNA-based sensors. I-motifs (iMs) are two intercalated parallel duplexes that are held together by hemiprotonated C-C base pairs. Previously, iMs were used as an accurate sensor for intracellular pH measurements. However, iM stability is moderate, which in turn limits its in vivo applications. Here, we report the rational design of a new substituted phenoxazine 2'-deoxynucleotide (i-clamp) for iM stabilization. This residue contains a C8-aminopropyl tether that interacts with the phosphate group within the neighboring chain without compromising base pairing. We studied the influence of i-clamp on pH-dependent stability for intra- and intermolecular iM structures and found the optimal positions for modification. Two i-clamps on opposite strands provide thermal stabilization up to 10-11°C at a pH of 5.8. Thus, we developed a new modification that shows significant iM-stabilizing effect both at strongly and mildly acidic pH and increases iM transition pH values. i-Clamp can be used for tuning iM-based pH probes or assembling extra stable iM structures for various applications.
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Affiliation(s)
- Vladimir B Tsvetkov
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
- Department of Molecular Virology, FSBI Research Institute of Influenza, Ministry of Health of Russian Federation, prof. Popov str. 15/17, Saint-Petersburg, 197376, Russia
- Polyelectrolytes and Biomedical Polymers Laboratory, A.V. Topchiev Institute of Petrochemical Synthesis, RAS, Leninsky prospect str. 29, Moscow 119991, Russia
| | - Timofei S Zatsepin
- Center for Translational Biomedicine, Skolkovo Institute of Science and Technology, 3 Nobel street, Skolkovo, Moscow 143026, Russia
- Chemistry Department, Lomonosov Moscow State University, Leninskie gory str. 1–3, Moscow 119992, Russia
| | - Evgeny S Belyaev
- Frumkin Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Science, Leninsky prospect str. 31, Moscow 119071 Russia
| | - Yury I Kostyukevich
- Center for Translational Biomedicine, Skolkovo Institute of Science and Technology, 3 Nobel street, Skolkovo, Moscow 143026, Russia
| | - George V Shpakovski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russia
| | - Victor V Podgorsky
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
| | - Galina E Pozmogova
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
| | - Anna M Varizhuk
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, Moscow 119991, Russia
| | - Andrey V Aralov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russia
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196
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Structural and theoretical study of 1-[1-oxo-3-phenyl-(2-benzosulfonamide)-propyl amido] – anthracene-9,10-dione to be i-motif inhibitor. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.12.054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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197
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Non-canonical DNA structures: Comparative quantum mechanical study. Biophys Chem 2018; 235:19-28. [DOI: 10.1016/j.bpc.2018.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 11/21/2022]
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Zamiri B, Mirceta M, Abu-Ghazalah R, Wold MS, Pearson CE, Macgregor RB. Stress-induced acidification may contribute to formation of unusual structures in C9orf72-repeats. Biochim Biophys Acta Gen Subj 2018; 1862:1482-1491. [PMID: 29550431 DOI: 10.1016/j.bbagen.2018.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 02/22/2018] [Accepted: 03/04/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Expansion of the C9orf72 hexanucleotide repeat (GGGGCC)n·(GGCCCC)n is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Both strands of the C9orf72 repeat have been shown to form unusual DNA and RNA structures that are thought to be involved in mutagenesis and/or pathogenesis. We previously showed that the C-rich DNA strands from the C9orf72 repeat can form four-stranded quadruplexes at neutral pH. The cytosine residues become protonated under slightly acidic pH (pH 4.5-6.2), facilitating the formation of intercalated i-motif structures. METHODS Using CD spectroscopy, UV melting, and gel electrophoresis, we demonstrate a pH-induced structural transition of the C-rich DNA strand of the C9orf72 repeat at pHs reported to exist in living cells under stress, including during neurodegeneration and cancer. RESULTS We show that the repeats with lengths of 4, 6, and 8 units, form intercalated quadruplex i-motifs at low pH (pH < 5) and monomolecular hairpins and monomolecular quadruplexes under neutral-basic conditions (pH ≥ 8). Furthermore, we show that the human replication protein A (RPA) binds to the G-rich and C-rich DNA strands under acidic conditions, suggesting that it can bind to i-motif structures. CONCLUSIONS In the proper sequence context, i-motif structures can form at pH values found in some cells in vivo. GENERAL SIGNIFICANCE DNA conformational plasticity exists over broad range of solution conditions.
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Affiliation(s)
- Bita Zamiri
- Graduate Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Mila Mirceta
- Program of Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada; Program of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | - Rashid Abu-Ghazalah
- W. Booth School of Engineering Technology Practice and Technology, McMaster University, Hamilton, Ontario L8S 0A3, Canada
| | - Marc S Wold
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Christopher E Pearson
- Program of Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada; Program of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | - Robert B Macgregor
- Graduate Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada.
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Harroun SG, Prévost-Tremblay C, Lauzon D, Desrosiers A, Wang X, Pedro L, Vallée-Bélisle A. Programmable DNA switches and their applications. NANOSCALE 2018; 10:4607-4641. [PMID: 29465723 DOI: 10.1039/c7nr07348h] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
DNA switches are ideally suited for numerous nanotechnological applications, and increasing efforts are being directed toward their engineering. In this review, we discuss how to engineer these switches starting from the selection of a specific DNA-based recognition element, to its adaptation and optimisation into a switch, with applications ranging from sensing to drug delivery, smart materials, molecular transporters, logic gates and others. We provide many examples showcasing their high programmability and recent advances towards their real life applications. We conclude with a short perspective on this exciting emerging field.
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Affiliation(s)
- Scott G Harroun
- Laboratory of Biosensors & Nanomachines, Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
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Guo F, Li Q, Zhou C. Synthesis and biological applications of fluoro-modified nucleic acids. Org Biomol Chem 2018; 15:9552-9565. [PMID: 29086791 DOI: 10.1039/c7ob02094e] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Owing to the unique physical properties of a fluorine atom, incorporating fluoro-modifications into nucleic acids offers striking biophysical and biochemical features, and thus significantly extends the breadth and depth of biological applications of nucleic acids. In this review, fluoro-modified nucleic acids that have been synthesized through either solid phase synthesis or the enzymatic approach are briefly summarised, followed by a section describing their biomedical applications in nucleic acid-based therapeutics, 18F PET imaging and mechanistic studies of DNA modifying enzymes. In the last part, the utility of 19F NMR and MRI for probing the structure, dynamics and molecular interactions of fluorinated nucleic acids is reviewed.
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Affiliation(s)
- Fengmin Guo
- State Key Laboratory of Elemento-Organic Chemistry and Department of Chemical Biology, College of Chemistry, Nankai University, Tianjin 300071, China.
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