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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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2
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Malik S, Kumar V, Liu CH, Shih KC, Krueger S, Nieh MP, Bahal R. Head on Comparison of Self- and Nano-assemblies of Gamma Peptide Nucleic Acid Amphiphiles. ADVANCED FUNCTIONAL MATERIALS 2022; 32:2109552. [PMID: 35210986 PMCID: PMC8863176 DOI: 10.1002/adfm.202109552] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Indexed: 05/14/2023]
Abstract
Peptide nucleic acids (PNAs) are nucleic acid analogs with superior hybridization properties and enzymatic stability than deoxyribonucleic acid (DNA). In addition to gene targeting applications, PNAs have garnered significant attention as bio-polymer due to the Watson-Crick -based molecular recognition and flexibility of synthesis. Here, we engineered PNA amphiphiles using chemically modified gamma PNA (8 mer in length) containing hydrophilic diethylene glycol units at the gamma position and covalently conjugated lauric acid (C12) as a hydrophobic moiety. Gamma PNA (γPNA) amphiphiles self-assemble into spherical vesicles. Further, we formulate nano-assemblies using the amphiphilic γPNA as a polymer via ethanol injection-based protocols. We perform comprehensive head-on comparison of the physicochemical and cellular uptake properties of PNA derived self- and nano-assemblies. Small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS) analysis reveal ellipsoidal morphology of γPNA nano-assemblies that results in superior cellular delivery compate to the spherical self-assembly. Next, we compare the functional activities of γPNA self-and nano-assemblies in lymphoma cells via multiple endpoints, including gene expression, cell viability, and apoptosis-based assays. Overall, we establish that γPNA amphiphile is a functionally active bio-polymer to formulate nano-assemblies for a wide range of biomedical applications.
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Affiliation(s)
- Shipra Malik
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, 06269, USA
| | - Vikas Kumar
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, 06269, USA
| | - Chung-Hao Liu
- Polymer Program, Institute of Material Sciences, University of Connecticut, 191 Auditorium Road, Storrs, CT, 06269, USA
| | - Kuo-Chih Shih
- Polymer Program, Institute of Material Sciences, University of Connecticut, 191 Auditorium Road, Storrs, CT, 06269, USA
| | - Susan Krueger
- National Institute of Standards and Technology, Gaithersburg, MD 20899-6102, USA
| | - Mu-Ping Nieh
- Polymer Program, Institute of Material Sciences, University of Connecticut, 191 Auditorium Road, Storrs, CT, 06269, USA
| | - Raman Bahal
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, 06269, USA
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Bhingardeve P, Jain P, Ganesh KN. Molecular Assembly of Triplex of Duplexes from Homothyminyl-Homocytosinyl Cγ( S/ R)-Bimodal Peptide Nucleic Acids with dA 8/dG 6 and the Cell Permeability of Bimodal Peptide Nucleic Acids. ACS OMEGA 2021; 6:19757-19770. [PMID: 34368563 PMCID: PMC8340421 DOI: 10.1021/acsomega.1c02451] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 07/05/2021] [Indexed: 05/08/2023]
Abstract
Peptide nucleic acids (PNAs) are analogues of DNA with a neutral acyclic polyamide backbone containing nucleobases attached through a t-amide link on repeating units of aminoethylglycine (aeg). They bind to complementary DNA or RNA in a sequence-specific manner to form duplexes with higher stablity than DNA:DNA and DNA:RNA hybrids. We have recently explored a new type of PNA termed bimodal PNA (bm-PNA) designed with two nucleobases per aeg repeating unit of PNA oligomer and attached at Cα or Cγ of each aeg unit through a spacer sidechain. We demonstrated that Cγ-bimodal PNA oligomers with mixed nucleobase sequences bind concurrently two different complementary DNAs, forming double duplexes, one from each t-amide and Cγ face, sharing a common PNA backbone. In such bm-PNA:DNA ternary complexes, the two duplexes show higher thermal stability than individual duplexes. Herein, we show that Cγ(S/R)-bimodal PNAs with homothymines (T8) on a t-amide face and homocytosine (C6) on a Cγ-face form a conjoined pentameric complex consisting of a triplex (bm-PNA-T8)2:dA8 and two duplexes of bm-PNA-C6:dG6. The pentameric complex [dG6:Cγ(S/R)-bm-PNA:dA8:Cγ(S/R)-bm-PNA:dG6] exhibits higher thermal stability than the individual triplex and duplex, with Cγ(S)-bm-PNA complexes being more stable than Cγ(R)-bm-PNA complexes. The conjoined duplexes of Cγ-bimodal PNAs can be used to generate novel higher-order assemblies with DNA and RNA. The Cγ(S/R)-bimodal PNAs are shown to enter MCF7 and NIH 3T3 cells and exhibit low toxicity to cells.
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Affiliation(s)
- Pramod Bhingardeve
- Indian
Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
| | - Prashant Jain
- Indian
Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
| | - Krishna N. Ganesh
- Indian
Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
- Indian
Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Mangalam, Tirupati 517507, India
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4
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Kim KT, Angerani S, Winssinger N. A minimal hybridization chain reaction (HCR) system using peptide nucleic acids. Chem Sci 2021; 12:8218-8223. [PMID: 34194712 PMCID: PMC8208298 DOI: 10.1039/d1sc01269j] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/06/2021] [Indexed: 12/28/2022] Open
Abstract
The HCR represents a powerful tool for amplification in DNA-based circuitry and sensing applications, yet requires the use of long DNA sequences to grant hairpin metastability. Here we describe a minimal HCR system based on peptide nucleic acids (PNAs). A system comprising a 5-mer stem and 5-mer loop/toehold hairpins was found to be suitable to achieve rapid amplification. These hairpins were shown to yield >10-fold amplification in 2 h and be suitable for the detection of a cancer biomarker on live cells. The use of γ-peg-modified PNA was found to be beneficial.
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Topham CM, Smith JC. Peptide nucleic acid Hoogsteen strand linker design for major groove recognition of DNA thymine bases. J Comput Aided Mol Des 2021; 35:355-369. [PMID: 33624202 DOI: 10.1007/s10822-021-00375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
Sequence-specific targeting of double-stranded DNA and non-coding RNA via triple-helix-forming peptide nucleic acids (PNAs) has attracted considerable attention in therapeutic, diagnostic and nanotechnological fields. An E-base (3-oxo-2,3-dihydropyridazine), attached to the polyamide backbone of a PNA Hoogsteen strand by a side-chain linker molecule, is typically used in the hydrogen bond recognition of the 4-oxo group of thymine and uracil nucleic acid bases in the major groove. We report on the application of quantum chemical computational methods, in conjunction with spatial constraints derived from the experimental structure of a homopyrimidine PNA·DNA-PNA hetero-triplex, to investigate the influence of linker flexibility on binding interactions of the E-base with thymine and uracil bases in geometry-optimised model systems. Hydrogen bond formation between the N2 E-base atom and target pyrimidine base 4-oxo groups in model systems containing a β-alanine linker (J Am Chem Soc 119:11116, 1997) was found to incur significant internal strain energy and the potential disruption of intra-stand aromatic base stacking interactions in an oligomeric context. In geometry-optimised model systems containing a 3-trans olefin linker (Bioorg Med Chem Lett 14:1551, 2004) the E-base swung out away from the target pyrimidine bases into the solvent. These findings are in qualitative agreement with calorimetric measurements in hybridisation experiments at T-A and U-A inversion sites. In contrast, calculations on a novel 2-cis olefin linker design indicate that it could permit simultaneous E-base hydrogen bonding with the thymine 4-oxo group, circumvention and solvent screening of the thymine 5-methyl group, and maintenance of triplex intra-stand base stacking interactions.
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Affiliation(s)
- Christopher M Topham
- Molecular Forces Consulting, 24 Avenue Jacques Besse, 81500, Lavaur, France.
- Computational Molecular Biophysics, IWR Der Universität Heidelberg, Im Neuenheimer Feld 368, 69120, Heidelberg, Germany.
- Center for Molecular Biophysics, University of Tennessee / Oak Ridge National Laboratory, P.O.Box 2008, Oak Ridge, TN, 37831-6309, USA.
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN, 37996, USA.
| | - Jeremy C Smith
- Computational Molecular Biophysics, IWR Der Universität Heidelberg, Im Neuenheimer Feld 368, 69120, Heidelberg, Germany
- Center for Molecular Biophysics, University of Tennessee / Oak Ridge National Laboratory, P.O.Box 2008, Oak Ridge, TN, 37831-6309, USA
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN, 37996, USA
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6
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Wassermann B, Rybakova D, Adam E, Zachow C, Bernhard M, Müller M, Mancinelli R, Berg G. Studying Seed Microbiomes. Methods Mol Biol 2021; 2232:1-21. [PMID: 33161534 DOI: 10.1007/978-1-0716-1040-4_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Recent studies indicate that seed microbiomes affect germination and plant performance. However, the interplay between seed microbiota and plant health is still poorly understood. To get a complete picture of the system, a comprehensive analysis is required, comprising culture-dependent and culture-independent techniques. In this chapter, we provide a combination of methods that are established and optimized for the analysis of the seed microbiome. These include methods to: (1) activate and cultivate dormant seed microbiota, (2) analyze microbiota in germinated seeds (with and without substrate), (3) quantify microbial DNA via real-time PCR, (4) deplete host DNA for amplicon and metagenome analysis, and (5) visualize seed endophytes in microtomed sections using fluorescent in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM). A deep understanding of the seed microbiome and its functions can help in developing new seed treatments and breeding strategies for sustainable agriculture.
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Affiliation(s)
- Birgit Wassermann
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
| | - Daria Rybakova
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
| | - Eveline Adam
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
| | | | - Maria Bernhard
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
| | - Maria Müller
- Department of Plant Sciences, Institute of Biology, NAWI Graz, University of Graz, Graz, Austria
| | - Riccardo Mancinelli
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
| | - Gabriele Berg
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.
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Bhingardeve P, Madhanagopal BR, Ganesh KN. Cγ( S/ R)-Bimodal Peptide Nucleic Acids (Cγ- bm-PNA) Form Coupled Double Duplexes by Synchronous Binding to Two Complementary DNA Strands. J Org Chem 2020; 85:13680-13693. [PMID: 32985197 DOI: 10.1021/acs.joc.0c01853] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Peptide nucleic acids (PNAs) are linear equivalents of DNA with a neutral acyclic polyamide backbone that has nucleobases attached via tert-amide link on repeating units of aminoethylglycine. They bind complementary DNA or RNA with sequence specificity to form hybrids that are more stable than the corresponding DNA/RNA self-duplexes. A new type of PNA termed bimodal PNA [Cγ(S/R)-bm-PNA] is designed to have a second nucleobase attached via amide spacer to a side chain at Cγ on the repeating aeg units of PNA oligomer. Cγ-bimodal PNA oligomers that have two nucleobases per aeg unit are demonstrated to concurrently bind two different complementary DNAs, to form duplexes from both tert-amide side and Cγ side. In such PNA:DNA ternary complexes, the two duplexes share a common PNA backbone. The ternary DNA 1:Cγ(S/R)-bm-PNA:DNA 2 complexes exhibit better thermal stability than the isolated duplexes, and the Cγ(S)-bm-PNA duplexes are more stable than Cγ(R)-bm-PNA duplexes. Bimodal PNAs are first examples of PNA analogues that can form DNA2:PNA:DNA1 double duplexes via recognition through natural bases. The conjoined duplexes of Cγ-bimodal PNAs can be used to generate novel higher-level assemblies.
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Affiliation(s)
- Pramod Bhingardeve
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Bharath Raj Madhanagopal
- Indian Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Mangalam, Tirupati 517507, India
| | - Krishna N Ganesh
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pune 411008, India.,Indian Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Mangalam, Tirupati 517507, India
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Ito Y. Development of Ruthenium Complex-Conjugated Oligonucleotides. J SYN ORG CHEM JPN 2020. [DOI: 10.5059/yukigoseikyokaishi.78.898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yuta Ito
- Faculty of Pharmaceutical Sciences, Tokushima Bunri Univeristy
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