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Tamez A, Nilsson L, Mihailescu MR, Evanseck JD. Parameterization of the miniPEG-Modified γPNA Backbone: Toward Induced γPNA Duplex Dissociation. J Chem Theory Comput 2023. [PMID: 37195939 DOI: 10.1021/acs.jctc.2c01163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
γ-Modified peptide nucleic acids (γPNAs) serve as potential therapeutic agents against genetic diseases. Miniature poly(ethylene glycol) (miniPEG) has been reported to increase solubility and binding affinity toward genetic targets, yet details of γPNA structure and dynamics are not understood. Within our work, we parameterized missing torsional and electrostatic terms for the miniPEG substituent on the γ-carbon atom of the γPNA backbone in the CHARMM force field. Microsecond timescale molecular dynamics simulations were carried out on six miniPEG-modified γPNA duplexes from NMR structures (PDB ID: 2KVJ). Three NMR models for the γPNA duplex (PDB ID: 2KVJ) were simulated as a reference for structural and dynamic changes captured for the miniPEG-modified γPNA duplex. Principal component analysis performed on the γPNA backbone atoms identified a single isotropic conformational substate (CS) for the NMR simulations, whereas four anisotropic CSs were identified for the ensemble of miniPEG-modified γPNA simulations. The NMR structures were found to have a 23° helical bend toward the major groove, consistent with our simulated CS structure of 19.0°. However, a significant difference between simulated methyl- and miniPEG-modified γPNAs involved the opportunistic invasion of miniPEG through the minor and major groves. Specifically, hydrogen bond fractional analysis showed that the invasion was particularly prone to affect the second G-C base pair, reducing the Watson-Crick base pair hydrogen bond by 60% over the six simulations, whereas the A-T base pairs decreased by only 20%. Ultimately, the invasion led to base stack reshuffling, where the well-ordered base stacking was reduced to segmented nucleobase stacking interactions. Our 6 μs timescale simulations indicate that duplex dissociation suggests the onset toward γPNA single strands, consistent with the experimental observation of decreased aggregation. To complement the insight of miniPEG-modified γPNA structure and dynamics, the new miniPEG force field parameters allow for further exploration of such modified γPNA single strands as potential therapeutic agents against genetic diseases.
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Affiliation(s)
- Angel Tamez
- Center for Computational Sciences and the Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
| | - Lennart Nilsson
- Department of Biosciences and Nutrition, Karolinska Institute, Solnavägen 1, 171 77 Solna, Sweden
| | - Mihaela-Rita Mihailescu
- Center for Computational Sciences and the Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
| | - Jeffrey D Evanseck
- Center for Computational Sciences and the Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
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2
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Kulkarni P, Datta D, Ganesh KN. Gemdimethyl Peptide Nucleic Acids (α/β/γ -gdm-PNA): E/Z-Rotamers Influence the Selectivity in the Formation of Parallel/Antiparallel gdm-PNA:DNA/RNA Duplexes. ACS OMEGA 2022; 7:40558-40568. [PMID: 36385799 PMCID: PMC9647847 DOI: 10.1021/acsomega.2c05873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 10/17/2022] [Indexed: 05/29/2023]
Abstract
Peptide nucleic acids (PNAs) consist of an aminoethylglycine (aeg) backbone to which the nucleobases are linked through a tertiary amide group and bind to complementary DNA/RNA in a sequence-specific manner. The flexible aeg backbone has been the target for several chemical modifications of the PNA to improve its properties such as specificity, solubility, etc. PNA monomers exhibit a mixture of two rotamers (Z/E) arising from the restricted rotation around the tertiary amide N-CO bond. We have recently demonstrated that achiral gemdimethyl substitution at the α, β, and γ sites on the aeg backbone induces exclusive Z (α-gdm)- or E-rotamer (β-gdm) selectivity at the monomer level. It is now shown that γ/β-gdm-PNA:DNA parallel duplexes are more stable than the analogous antiparallel duplexes, while γ/β-gdm-PNA:RNA antiparallel duplexes are more stable than parallel duplexes. Furthermore, the γ/β-gdm-PNA:RNA duplexes are more stable than the γ/β-gdm-PNA:DNA duplexes. These results with γ/β-gdm-PNA are the reverse of those previously seen with α-gdm-PNA oligomers that stabilized antiparallel α-gdm-PNA:DNA duplexes compared to α-gdm-PNA:RNA duplexes. The stability of antiparallel/parallel PNA:DNA/RNA duplexes is correlated with the preference for Z/E-rotamer selectivity in α/β-gdm-PNA monomers, with Z-rotamers (α-gdm) leading to antiparallel duplexes and E-rotamers (β/γ-gdm) leading to parallel duplexes. The results highlight the role and importance of Z- and E-rotamers in controlling the structural preferences of PNA:DNA/RNA duplexes.
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Affiliation(s)
- Pradnya Kulkarni
- Chemistry
Department, Indian Institute of Science
Education and Research (IISER) Tirupati, Karkambadi Road, Mangalam, Tirupati517507, India
| | - Dhrubajyoti Datta
- Chemistry
Department, Indian Institute of Science
Education and Research (IISER) Tirupati, Karkambadi Road, Mangalam, Tirupati517507, India
| | - Krishna N. Ganesh
- Indian
Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune411008, India
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3
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Suparpprom C, Vilaivan T. Perspectives on conformationally constrained peptide nucleic acid (PNA): insights into the structural design, properties and applications. RSC Chem Biol 2022; 3:648-697. [PMID: 35755191 PMCID: PMC9175113 DOI: 10.1039/d2cb00017b] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/17/2022] [Indexed: 11/21/2022] Open
Abstract
Peptide nucleic acid or PNA is a synthetic DNA mimic that contains a sequence of nucleobases attached to a peptide-like backbone derived from N-2-aminoethylglycine. The semi-rigid PNA backbone acts as a scaffold that arranges the nucleobases in a proper orientation and spacing so that they can pair with their complementary bases on another DNA, RNA, or even PNA strand perfectly well through the standard Watson-Crick base-pairing. The electrostatically neutral backbone of PNA contributes to its many unique properties that make PNA an outstanding member of the xeno-nucleic acid family. Not only PNA can recognize its complementary nucleic acid strand with high affinity, but it does so with excellent specificity that surpasses the specificity of natural nucleic acids and their analogs. Nevertheless, there is still room for further improvements of the original PNA in terms of stability and specificity of base-pairing, direction of binding, and selectivity for different types of nucleic acids, among others. This review focuses on attempts towards the rational design of new generation PNAs with superior performance by introducing conformational constraints such as a ring or a chiral substituent in the PNA backbone. A large collection of conformationally rigid PNAs developed during the past three decades are analyzed and compared in terms of molecular design and properties in relation to structural data if available. Applications of selected modified PNA in various areas such as targeting of structured nucleic acid targets, supramolecular scaffold, biosensing and bioimaging, and gene regulation will be highlighted to demonstrate how the conformation constraint can improve the performance of the PNA. Challenges and future of the research in the area of constrained PNA will also be discussed.
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Affiliation(s)
- Chaturong Suparpprom
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Naresuan University, Tah-Poe District, Muang Phitsanulok 65000 Thailand
- Organic Synthesis Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University Phayathai Road Pathumwan Bangkok 10330 Thailand
| | - Tirayut Vilaivan
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Naresuan University, Tah-Poe District, Muang Phitsanulok 65000 Thailand
- Organic Synthesis Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University Phayathai Road Pathumwan Bangkok 10330 Thailand
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4
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Kulkarni P, Datta D, Ramabhadran RO, Ganesh K. Gem-dimethyl peptide nucleic acid (α/β/γ- gdm-PNA) monomers: synthesis and the role of gdm-substituents in preferential stabilisation of Z/ E-rotamers. Org Biomol Chem 2021; 19:6534-6545. [PMID: 34259296 DOI: 10.1039/d1ob01097b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The flexible backbone of aminoethylglycine (aeg) PNA upon substitution becomes sterically constrained to enable conformational pre-organization for preferential binding to DNA or RNA. The bulky gem-dimethyl (gdm) substituent on carbons adjacent to the t-amide sidechain either at Cα (glycyl) or Cβ/Cγ (aminoethylene) sides may influence the Z/E rotamer ratio arising from a restricted rotation around the t-amide bond. Employing 2D NMR (NOESY), it is shown here that the Cα-gdm-PNA-T monomer exhibits exclusively the Z-rotamer, while the Cβ-gdm-PNA-T monomer shows only the E-rotamer. The unsubstituted aeg-PNA-T and Cγ-gdm-PNA-T monomers display a mixture of Z/E rotamers. The rotamers with t-amide carbonyl pointing towards the gem-dimethyl group always prevailed. The results are supported by computational studies that suggested that the preferred rotamers are the outcome of a net energetic benefit from the stabilising n-π* interactions of carbonyls (amide backbone and t-amide sidechain), and C-HO interactions and the destabilising steric clash of gem-dimethyl groups with the t-amido methylene group. The E-rotamer structure in Cγ-gdm is also characterised by X-ray crystallography. The exclusive E-rotamer for the Cβ-gdm monomer seen in solution here is the first such example among several modified PNA monomers. Since the conformation of the sidechain is important for inducing base stacking and effective base pairing, the exclusive E-rotamer in the Cβ-gdm monomer may have significance in the properties of the derived PNA : DNA/RNA duplexes with all E-rotamers.
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Affiliation(s)
- Pradnya Kulkarni
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
| | - Dhrubajyoti Datta
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
| | - Raghunath O Ramabhadran
- Chemistry Department and CAMOST, Indian Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Mangalam, Tirupati 517507, India.
| | - Krishna Ganesh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India and Chemistry Department and CAMOST, Indian Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Mangalam, Tirupati 517507, India.
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5
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Das A, Pradhan B. Evolution of peptide nucleic acid with modifications of its backbone and application in biotechnology. Chem Biol Drug Des 2020; 97:865-892. [PMID: 33314595 DOI: 10.1111/cbdd.13815] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/17/2020] [Accepted: 12/05/2020] [Indexed: 01/23/2023]
Abstract
Peptide nucleic acids (PNAs) are getting prodigious interest currently in the biomedical and diagnostic field as an extremely powerful tool because of their potentiality to hybridize with natural nucleic acids. Although PNA has strong affinity and sequence specificity to DNA/RNA, there is a considerable ongoing effort to further enhance their special chemical and biological properties for potential application in numerous fields, notably in the field of therapeutics. The toolbox for backbone modified PNAs synthesis has been extended substantially in recent decades, providing a more efficient synthesis of peptides with numerous scaffolds and modifications. This paper reviews the various strategies that have been developed so far for the modification of the PNA backbone, challenging the search for new PNA systems with improved chemical and physical properties lacking in the original aegPNA backbone. The various practical issues and limitations of different PNA systems are also summarized. The focus of this review is on the evolution of PNA by its backbone modification to improve the cellular uptake, sequence specificity, and compatibility of PNA to bind to DNA/RNA. Finally, an insight was also gained into major applications of backbone modified PNAs for the development of biosensors.
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Affiliation(s)
- Anuradha Das
- National Institute of Science Education and Research Bhubaneswar (HBNI), Bhubaneswar, India
| | - Biswaranjan Pradhan
- S. K. Dash Center of Excellence of Biosciences and Engineering & Technology, Indian Institute of Technology Bhubaneswar, Bhubaneswar, India
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6
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Abdelbaky AS, Prokhorov IA, Gnuskova EV, Esipova OV, Kirillova YG. Convenient and Efficient Syntheses of Peptide Nucleic Acid Purine Monomers. CURR ORG CHEM 2019. [DOI: 10.2174/1385272823666191014161442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Currently, peptide nucleic acids (PNAs) play an important role as therapeutic
agents, molecular tools for diagnosis and detection of genetic diseases as well as in biosensor
probes. This research aims to optimize the synthesis of aeg- and γ-(S)-Me PNA
monomers based on L-Ala, intended for oligomerization according to the Boc protocol.
The monomers were obtained through the condensation of the corresponding pseudopeptides
with carboxymethyl purine nucleic bases. During the work, the optimization of benzyloxycarbonyl-
N6-adenine-9-yl-acetic acid and benzyloxycarbonyl-N2-guanine-9-ylacetic
acid was carried out. The synthesis of benzyloxycarbonyl-N6-adenine-9-yl-acetic
acid was conducted in three stages based on adenine with an overall yield of 22%. At the
same time, the conditions for effective recrystallization of the mixture after alkylation of
benzyloxycarbonyl-N6-adenine with ethyl bromoacetic acid ether have been developed to isolate the desired
N9-regioisomer. Also, the optimization of a known method for producing benzyloxycarbonyl-N2-guanine-9-ylacetic
acid from 2-amino-6-chloropurine was carried out. The total yield of the five-stage scheme was 55%.
Condensation of aeg- and γ-(S)-Me pseudopeptides with benzyloxycarbonyl-N6-adenine-9-yl-acetic acid and
benzyloxycarbonyl-N2-guanine-9-yl-acetic acid was performed by the standard carbodiimide method,
DCC/HOBt in DMF followed by the removal of C-terminal methyl protective group by alkaline hydrolysis.
The structure of the new compounds obtained was confirmed by spectral analysis methods. This work provides
simple and optimized methods for obtaining protected carboxymethyl purine bases and increasing the efficiency
of the synthesis and synthesized purine PNA monomers in an acceptable yield.
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Affiliation(s)
- Ahmed S. Abdelbaky
- Department of Biotechnology and Industrial Pharmacy, M.V. Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, 119571 Moscow, Russian Federation
| | - Ivan A. Prokhorov
- Department of Biotechnology and Industrial Pharmacy, M.V. Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, 119571 Moscow, Russian Federation
| | - Elena V. Gnuskova
- Department of Biotechnology and Industrial Pharmacy, M.V. Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, 119571 Moscow, Russian Federation
| | - Olga V. Esipova
- Department of Biotechnology and Industrial Pharmacy, M.V. Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, 119571 Moscow, Russian Federation
| | - Yulia G. Kirillova
- Department of Biotechnology and Industrial Pharmacy, M.V. Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, 119571 Moscow, Russian Federation
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7
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Saarbach J, Masi D, Zambaldo C, Winssinger N. Facile access to modified and functionalized PNAs through Ugi-based solid phase oligomerization. Bioorg Med Chem 2017. [PMID: 28624242 DOI: 10.1016/j.bmc.2017.05.064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Peptide nucleic acids (PNAs) derivatized with functional molecules are increasingly used in diverse biosupramolecular applications. PNAs have proven to be highly tolerant to modifications and different applications benefit from the use of modified PNAs, in particular modifications at the γ position. Herein we report simple protocols to access modified PNAs from iterative Ugi couplings which allow modular modifications at the α, β or γ position of the PNA backbone from simple starting materials. We demonstrate the utility of the method with the synthesis of several bioactive small molecules (a peptide ligand, a kinase inhibitor and a glycan)-PNA conjugates.
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Affiliation(s)
- Jacques Saarbach
- Faculty of Science, Department of Organic Chemistry, NCCR Chemical Biology, University of Geneva, 30 quai Ernest Ansermet, Geneva, Switzerland
| | - Daniela Masi
- Faculty of Science, Department of Organic Chemistry, NCCR Chemical Biology, University of Geneva, 30 quai Ernest Ansermet, Geneva, Switzerland
| | - Claudio Zambaldo
- Faculty of Science, Department of Organic Chemistry, NCCR Chemical Biology, University of Geneva, 30 quai Ernest Ansermet, Geneva, Switzerland
| | - Nicolas Winssinger
- Faculty of Science, Department of Organic Chemistry, NCCR Chemical Biology, University of Geneva, 30 quai Ernest Ansermet, Geneva, Switzerland.
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8
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Wang X, Milne M, Martínez F, Scholl TJ, Hudson RHE. Synthesis of a poly(Gd( iii)-DOTA)–PNA conjugate as a potential MRI contrast agent via post-synthetic click chemistry functionalization. RSC Adv 2017. [DOI: 10.1039/c7ra09040d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
An operationally easy method provides poly(Gd3+chelate) PNA conjugates that form comb-like complexes with poly(rA) and demonstrate increased relaxivity.
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Affiliation(s)
- Xiaoxiao Wang
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Mark Milne
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Francisco Martínez
- Department of Medical Biophysics
- The Robarts Research Institute
- The University of Western Ontario
- London
- Canada
| | - Timothy J. Scholl
- Department of Medical Biophysics
- The Robarts Research Institute
- The University of Western Ontario
- London
- Canada
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9
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Sharma C, Awasthi SK. Versatility of peptide nucleic acids (PNAs): role in chemical biology, drug discovery, and origins of life. Chem Biol Drug Des 2016; 89:16-37. [PMID: 27490868 DOI: 10.1111/cbdd.12833] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/03/2016] [Accepted: 07/28/2016] [Indexed: 12/16/2022]
Abstract
This review briefly discussed nomenclature, synthesis, chemistry, and biophysical properties of a plethora of PNA derivatives reported since the discovery of aegPNA. Different synthetic methods and structural analogs of PNA synthesized till date were also discussed. An insight was gained into various chemical, physical, and biological properties of PNA which make it preferable over all other classes of modified nucleic acid analogs. Thereafter, various approaches with special attention to the practical constraints, characteristics, and inherent drawbacks leading to the delay in the development of PNA as gene therapeutic drug were outlined. An explicit account of the successful application of PNA in different areas of research such as antisense and antigene strategies, diagnostics, molecular probes, and so forth was described along with the current status of PNA as gene therapeutic drug. Further, the plausibility of the existence of PNA and its role in primordial chemistry, that is, origin of life was explored in an endeavor to comprehend the mystery and open up its deepest secrets ever engaging and challenging the human intellect. We finally concluded it with a discussion on the future prospects of PNA technology in the field of therapeutics, diagnostics, and origin of life.
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Affiliation(s)
- Chiranjeev Sharma
- Chemical Biology Laboratory, Department of Chemistry, University of Delhi, Delhi, India
| | - Satish Kumar Awasthi
- Chemical Biology Laboratory, Department of Chemistry, University of Delhi, Delhi, India
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Murayama K, Kashida H, Asanuma H. Acyclic
l-threoninol nucleic acid (l-aTNA) with suitable structural rigidity cross-pairs with DNA and RNA. Chem Commun (Camb) 2015; 51:6500-3. [DOI: 10.1039/c4cc09244a] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We newly synthesized l-aTNA, which showed the best affinity to DNA and RNA among acyclic nucleic acids with phosphodiester linkages.
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Affiliation(s)
- Keiji Murayama
- Department of Molecular Design and Engineering
- Graduate School of Engineering
- Nagoya University
- Nagoya 464-8603
- Japan
| | - Hiromu Kashida
- Department of Molecular Design and Engineering
- Graduate School of Engineering
- Nagoya University
- Nagoya 464-8603
- Japan
| | - Hiroyuki Asanuma
- Department of Molecular Design and Engineering
- Graduate School of Engineering
- Nagoya University
- Nagoya 464-8603
- Japan
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Sugiyama T, Kittaka A. Chiral peptide nucleic acids with a substituent in the N-(2-aminoethy)glycine backbone. Molecules 2012; 18:287-310. [PMID: 23271467 PMCID: PMC6269907 DOI: 10.3390/molecules18010287] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 11/16/2022] Open
Abstract
A peptide nucleic acid (PNA) is a synthetic nucleic acid mimic in which the sugar-phosphate backbone is replaced by a peptide backbone. PNAs hybridize to complementary DNA and RNA with higher affinity and superior sequence selectivity compared to DNA. PNAs are resistant to nucleases and proteases and have a low affinity for proteins. These properties make PNAs an attractive agent for biological and medical applications. To improve the antisense and antigene properties of PNAs, many backbone modifications of PNAs have been explored under the concept of preorganization. This review focuses on chiral PNAs bearing a substituent in the N-(2-aminoethyl)glycine backbone. Syntheses, properties, and applications of chiral PNAs are described.
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Affiliation(s)
- Toru Sugiyama
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +81-3-5465-8743
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, Kaga, Itabashi-ku, Tokyo 173-8605, Japan; E-Mail:
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