151
|
Moccia M, Adamo MFA, Saviano M. Insights on chiral, backbone modified peptide nucleic acids: Properties and biological activity. ARTIFICIAL DNA, PNA & XNA 2014; 5:e1107176. [PMID: 26752710 PMCID: PMC5329900 DOI: 10.1080/1949095x.2015.1107176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 12/14/2022]
Abstract
PNAs are emerging as useful synthetic devices targeting natural miRNAs. In particular 3 classes of structurally modified PNAs analogs are herein described, namely α, β and γ, which differ by their backbone modification. Their mode and binding affinity for natural nucleic acids and their use in medicinal chemistry as potential miRNA binders is discussed.
Collapse
Affiliation(s)
- Maria Moccia
- Consiglio Nazionale delle Ricerche-Institute of Cristallography; Bari, Italy
| | - Mauro F A Adamo
- Centre for Synthesis and Chemical Biology (CSCB); Department of Pharmaceutical & Medicinal Chemistry; Royal College of Surgeons in Ireland; Dublin, Ireland
| | - Michele Saviano
- Consiglio Nazionale delle Ricerche-Institute of Cristallography; Bari, Italy
| |
Collapse
|
152
|
Manicardi A, Corradini R. Effect of chirality in gamma-PNA: PNA interaction, another piece in the picture. ARTIFICIAL DNA, PNA & XNA 2014; 5:e1131801. [PMID: 26744081 PMCID: PMC5329894 DOI: 10.1080/1949095x.2015.1131801] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 12/23/2022]
Abstract
Modification of the PNA backbone can be used to broaden their utility by introducing new functional groups. In particular, gamma-modified PNA have been found to be quite effective in a number of applications, and exhibit particularly high DNA binding affinity. The introduction of one side chain imply that the achiral backbone of PNA becomes chiral, and binding properties depend on the stereochemistry. A new paper on gamma-modified PNA by Ly and co-workers complete the existing knowledge by displaying that in binding to complementary PNA stereochemical orthogonality can be demonstrated. This opens the way to the exploitation of stereochemical features in diagnostic assays and in nanofabrication.
Collapse
Affiliation(s)
- Alex Manicardi
- Dipartimento di Chimica; University of Parma; Parma, Italy
| | | |
Collapse
|
153
|
Vilaivan C, Srisuwannaket C, Ananthanawat C, Suparpprom C, Kawakami J, Yamaguchi Y, Tanaka Y, Vilaivan T. Pyrrolidinyl peptide nucleic acid with α/β-peptide backbone: A conformationally constrained PNA with unusual hybridization properties. ARTIFICIAL DNA, PNA & XNA 2014; 2:50-59. [PMID: 21912727 DOI: 10.4161/adna.2.2.16340] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 06/09/2011] [Accepted: 06/10/2011] [Indexed: 01/17/2023]
Abstract
We describe herein a new conformationally constrained analog of PNA carrying an alternating α/β amino acid backbone consisting of (2'R,4'R)-nucleobase-subtituted proline and (1S,2S)-2-aminocyclopentanecarboxylic acid (acpcPNA). The acpcPNA has been synthesized and evaluated for DNA, RNA and self-pairing properties by thermal denaturation experiments. It can form antiparallel hybrids with complementary DNA with high affinity and sequence specificity. Unlike other PNA systems, the thermal stability of acpcPNA·DNA hybrid is largely independent of G+C contents, and is generally higher than that of acpcPNA·RNA hybrid with the same sequence. Thermodynamic parameters analysis suggest that the A·T base pairs in the acpcPNA·DNA hybrids are enthalpically stabilized over G·C pairs. The acpcPNA also shows a hitherto unreported behavior, namely the inability to form self-pairing hybrids. These unusual properties should make the new acpcPNA a potentially useful candidate for various applications including microarray probes and antigene agents.
Collapse
Affiliation(s)
- Chotima Vilaivan
- Organic Synthesis Research Unit; Department of Chemistry; Faculty of Science; Chulalongkorn University; Patumwan, Bangkok, Thailand
| | | | | | | | | | | | | | | |
Collapse
|
154
|
Kuhn H, Sahu B, Rapireddy S, Ly DH, Frank-Kamenetskii MD. Sequence specificity at targeting double-stranded DNA with a γ-PNA oligomer modified with guanidinium G-clamp nucleobases. ARTIFICIAL DNA, PNA & XNA 2014; 1:45-53. [PMID: 21687526 DOI: 10.4161/adna.1.1.12444] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2010] [Revised: 05/19/2010] [Accepted: 05/24/2010] [Indexed: 11/19/2022]
Abstract
γ-PNA, a new class of peptide nucleic acids, promises to overcome previous sequence limitations of double-stranded DNA (dsDNA) targeting with PNA. To check the potential of γ-PNA, we have synthesized a biotinylated, pentadecameric γ-PNA of mixed sequence carrying three guanidinium G-clamp nucleobases. We have found that strand invasion reactions of the γ-PNA oligomer to its fully complementary target within dsDNA occurs with significantly higher binding rates than to targets containing single mismatches. Association of the PNA oligomer to mismatched targets does not go to completion but instead reaches a stationary level at or below 60%, even at conditions of very low ionic strength. Initial binding rates to both matched and mismatched targets experience a steep decrease with increasing salt concentration. We demonstrate that a linear DNA target fragment with the correct target sequence can be purified from DNA mixtures containing mismatched target or unrelated genomic DNA by affinity capture with streptavidin-coated magnetic beads. Similarly, supercoiled plasmid DNA is obtained with high purity from an initial sample mixture that included a linear DNA fragment with the fully complementary sequence. Based on the results obtained in this study we believe that γ-PNA has a great potential for specific targeting of chosen duplex DNA sites in a sequence-unrestricted fashion.
Collapse
Affiliation(s)
- Heiko Kuhn
- Center for Advanced Biotechnology; Department of Biomedical Engineering; Boston University; Boston, MA USA
| | | | | | | | | |
Collapse
|
155
|
Pham HH, Murphy CT, Sureshkumar G, Ly DH, Opresko PL, Armitage BA. Cooperative hybridization of γPNA miniprobes to a repeating sequence motif and application to telomere analysis. Org Biomol Chem 2014; 12:7345-7354. [PMID: 25115693 PMCID: PMC4162129 DOI: 10.1039/c4ob00953c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
GammaPNA oligomers having one or two repeats of the sequence AATCCC were designed to hybridize to DNA having one or more repeats of the complementary TTAGGG sequence found in the human telomere. UV melting curves and surface plasmon resonance experiments demonstrate high affinity and cooperativity for hybridization of these miniprobes to DNA having multiple complementary repeats. Fluorescence spectroscopy for Cy3-labeled miniprobes demonstrate increases in fluorescence intensity for assembling multiple short probes on a DNA target compared with fewer longer probes. The fluorescent γPNA miniprobes were then used to stain telomeres in metaphase chromosomes derived from U2OS cells possessing heterogeneous long telomeres and Jurkat cells harboring homogenous short telomeres. The miniprobes yielded comparable fluorescence intensity to a commercially available PNA 18mer probe in U2OS cells, but significantly brighter fluorescence was observed for telomeres in Jurkat cells. These results suggest that γPNA miniprobes can be effective telomere-staining reagents with applications toward analysis of critically short telomeres, which have been implicated in a range of human diseases.
Collapse
Affiliation(s)
- Ha H. Pham
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Connor T. Murphy
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Department of Environmental and Occupational Health, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15219
| | - Gopalsamy Sureshkumar
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Danith H. Ly
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Patricia L. Opresko
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Department of Environmental and Occupational Health, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15219
| | - Bruce A. Armitage
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| |
Collapse
|
156
|
Jain DR, Anandi V L, Lahiri M, Ganesh KN. Influence of pendant chiral C(γ)-(alkylideneamino/guanidino) cationic side-chains of PNA backbone on hybridization with complementary DNA/RNA and cell permeability. J Org Chem 2014; 79:9567-77. [PMID: 25221945 DOI: 10.1021/jo501639m] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Intrinsically cationic and chiral C(γ)-substituted peptide nucleic acid (PNA) analogues have been synthesized in the form of γ(S)-ethyleneamino (eam)- and γ(S)-ethyleneguanidino (egd)-PNA with two carbon spacers from the backbone. The relative stabilization (ΔTm) of duplexes from modified cationic PNAs as compared to 2-aminoethylglycyl (aeg)-PNA is better with complementary DNA (PNA:DNA) than with complementary RNA (PNA:RNA). Inherently, PNA:RNA duplexes have higher stability than PNA:DNA duplexes, and the guanidino PNAs are superior to amino PNAs. The cationic PNAs were found to be specific toward their complementary DNA target as seen from their significantly lower binding with DNA having single base mismatch. The differential binding avidity of cationic PNAs was assessed by the displacement of DNA duplex intercalated ethidium bromide and gel electrophoresis. The live cell imaging of amino/guanidino PNAs demonstrated their ability to penetrate the cell membrane in 3T3 and MCF-7 cells, and cationic PNAs were found to be accumulated in the vicinity of the nuclear membrane in the cytoplasm. Fluorescence-activated cell sorter (FACS) analysis of cell permeability showed the efficiency to be dependent upon the nature of cationic functional group, with guanidino PNAs being better than the amino PNAs in both cell lines. The results are useful to design new biofunctional cationic PNA analogues that not only bind RNA better but also show improved cell permeability.
Collapse
Affiliation(s)
- Deepak R Jain
- Chemical Biology Unit, Indian Institute of Science Education and Research , Dr Homi Bhabha Road, Pune 411008, Maharashtra, India
| | | | | | | |
Collapse
|
157
|
Méndez-Samperio P. Peptidomimetics as a new generation of antimicrobial agents: current progress. Infect Drug Resist 2014; 7:229-37. [PMID: 25210467 PMCID: PMC4155802 DOI: 10.2147/idr.s49229] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Antibiotic resistance is an increasing public health concern around the world. Rapid increase in the emergence of multidrug-resistant bacteria has been the target of extensive research efforts to develop a novel class of antibiotics. Antimicrobial peptides (AMPs) are small cationic amphiphilic peptides, which play an important role in the defense against bacterial infections through disruption of their membranes. They have been regarded as a potential source of future antibiotics, owing to a remarkable set of advantageous properties such as broad-spectrum activity, and they do not readily induce drug-resistance. However, AMPs have some intrinsic drawbacks, such as susceptibility to enzymatic degradation, toxicity, and high production cost. Currently, a new class of AMPs termed “peptidomimetics” have been developed, which can mimic the bactericidal mechanism of AMPs, while being stable to enzymatic degradation and displaying potent activity against multidrug-resistant bacteria. This review will focus on current findings of antimicrobial peptidomimetics. The potential future directions in the development of more potent analogs of peptidomimetics as a new generation of antimicrobial agents are also presented.
Collapse
Affiliation(s)
- Patricia Méndez-Samperio
- Department of Immunology, National School of Biological Sciences, National Polytechnic Institute, Mexico City, Mexico
| |
Collapse
|
158
|
Murphy CT, Gupta A, Armitage BA, Opresko PL. Hybridization of G-quadruplex-forming peptide nucleic acids to guanine-rich DNA templates inhibits DNA polymerase η extension. Biochemistry 2014; 53:5315-22. [PMID: 25068499 DOI: 10.1021/bi5006859] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The guanine quadruplex (G-quadruplex) is a highly stable secondary structure that forms in G-rich repeats of DNA, which can interfere with DNA processes, including DNA replication and transcription. We showed previously that short guanine-rich peptide nucleic acids (PNAs) can form highly stable hybrid quadruplexes with DNA. We hypothesized that such structures would provide a stronger block to polymerase extension on G-rich templates than a native DNA homoquadruplex because of the greater thermodynamic stability of the PNA-DNA hybrid structures. To test this, we analyzed the DNA primer extension activity of polymerase η, a translesion polymerase implicated in synthesis past G-quadruplex blocks, on DNA templates containing guanine repeats. We observed a PNA concentration-dependent decrease in the level of polymerase η extension to the end of the template and an increase in the level of polymerase η inhibition at the sequence prior to the G-rich repeats. In contrast, the addition of a complementary C-rich PNA that hybridizes to the G-rich repeats by Watson-Crick base pairing led to a decrease in the level of polymerase inhibition and an increase in the level of full-length extension products. The G-quadruplex-forming PNA exhibited inhibition (IC50=16.2±3.3 nM) of polymerase η DNA synthesis on the G-rich templates stronger than that of the established G-quadruplex-stabilizing ligand BRACO-19 (IC50=42.5±4.8 nM). Our results indicate that homologous PNA targeting of G-rich sequences creates stable PNA-DNA heteroquadruplexes that inhibit polymerase η extension more effectively than a DNA homoquadruplex. The implications of these results for the potential development of homologous PNAs as therapeutics for halting proliferating cancer cells are discussed.
Collapse
Affiliation(s)
- Connor T Murphy
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health , Pittsburgh, Pennsylvania 15219, United States
| | | | | | | |
Collapse
|
159
|
Abstract
Incorporating a cyclopentane ring into the two-carbon unit of a peptide nucleic acid backbone increases its binding affinity to complementary nucleic acid sequences. This approach is a general method to improve binding and can be applied at either purine or pyrimidine bases.
Collapse
Affiliation(s)
- Ethan A Englund
- Section on Synthetic Bioactive Molecules, Laboratory of Bioorganic Chemistry, NIDDK, NIH, DHHS, Bethesda, MD, USA
| | | | | |
Collapse
|
160
|
Abstract
Chiral open-chain PNAs have been shown to have improved properties in terms of control of helical handedness, DNA affinity, sequence selectivity, and cellular uptake. They can be synthesized either using preformed chiral monomers or by means of a submonomeric strategy. The former is preferred when only a stereogenic center is present at C-5, whereas for PNA-bearing substituents at C-2, the submonomeric approach is preferred, since racemization, generally occurring during the solid-phase synthesis, can be minimized by this procedure. Here we describe the protocols for the synthesis of PNA oligomers containing C-2- or C-5- (or both) modified monomers and a GC method for checking the optical purity of C-2-modified PNAs.
Collapse
|
161
|
De Costa NTS, Heemstra JM. Differential DNA and RNA sequence discrimination by PNA having charged side chains. Bioorg Med Chem Lett 2014; 24:2360-3. [PMID: 24731279 DOI: 10.1016/j.bmcl.2014.03.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 12/14/2022]
Abstract
PNA sequences modified with charged side chains were evaluated for base-pairing sequence selectivity under physiological conditions. PNA having negatively charged aspartic acid side chains shows higher selectivity with RNA, while PNA having positively charged lysine side chains shows higher selectivity with DNA. These observations provide insight into the binding selectivity of modified PNA in antisense and antigene applications.
Collapse
Affiliation(s)
- N Tilani S De Costa
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA; Center for Cell and Genome Science, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Jennifer M Heemstra
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA; Center for Cell and Genome Science, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
| |
Collapse
|
162
|
Bahal R, McNeer NA, Ly DH, Saltzman WM, Glazer PM. Nanoparticle for delivery of antisense γPNA oligomers targeting CCR5. ARTIFICIAL DNA, PNA & XNA 2014; 4:49-57. [PMID: 23954968 DOI: 10.4161/adna.25628] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of a new class of peptide nucleic acids (PNAs), i.e., gamma PNAs (γPNAs), creates the need for a general and effective method for its delivery into cells for regulating gene expression in mammalian cells. Here we report the antisense activity of a recently developed hydrophilic and biocompatible diethylene glycol (miniPEG)-based gamma peptide nucleic acid called MPγPNAs via its delivery by poly(lactide-co-glycolide) (PLGA)-based nanoparticle system. We show that MPγPNA oligomers designed to bind to the selective region of chemokine receptor 5 (CC R5) transcript, induce potent and sequence-specific antisense effects as compared with regular PNA oligomers. In addition, PLGA nanoparticle delivery of MPγPNAs is not toxic to the cells. The findings reported in this study provide a combination of γPNA technology and PLGA-based nanoparticle delivery method for regulating gene expression in live cells via the antisense mechanism.
Collapse
|
163
|
Abstract
Peptide nucleic acids (PNAs) are attractive, as compared to other classes of oligonucleotides that have been developed to date, in that they are relatively easy to synthesize and modify, hybridize to DNA and RNA with high affinity and sequence selectivity, and are resistant to enzymatic degradation by proteases and nucleases; however, the downside is that they are only moderately soluble in aqueous solution. Herein we describe the protocols for synthesizing the second-generation γPNAs, both the monomers and oligomers, containing MiniPEG side chain with considerable improvements in water solubility, biocompatibility, and hybridization properties.
Collapse
Affiliation(s)
- Arunava Manna
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, USA
| | | | | | | |
Collapse
|
164
|
Michaelis J, Roloff A, Seitz O. Amplification by nucleic acid-templated reactions. Org Biomol Chem 2014; 12:2821-33. [DOI: 10.1039/c4ob00096j] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Nucleic acid-templated reactions that proceed with turnover provide a means for signal amplification, which facilitates the use and detection of biologically occurring DNA/RNA molecules.
Collapse
Affiliation(s)
- Julia Michaelis
- Institut für Chemie der Humboldt-Universität zu Berlin
- 12489-Berlin, Germany
| | - Alexander Roloff
- Institut für Chemie der Humboldt-Universität zu Berlin
- 12489-Berlin, Germany
| | - Oliver Seitz
- Institut für Chemie der Humboldt-Universität zu Berlin
- 12489-Berlin, Germany
| |
Collapse
|
165
|
Affiliation(s)
- Krishna N. Ganesh
- Indian Institute of Science Education and Research, Division of Chemistry, 900, NCL Innovation Park, Dr Homi Bhabha Road, Pune, Maharashtra India
| | - Yamuna Krishnan
- National Centre for Biological Sciences,
Biophysics, Biochemistry and Bioinformatics, TIFR,
GKVK Campus, Bellary Road, Bangalore 560065, Karnataka, India
| |
Collapse
|
166
|
Murayama K, Tanaka Y, Toda T, Kashida H, Asanuma H. Highly Stable Duplex Formation by Artificial Nucleic Acids Acyclic Threoninol Nucleic Acid (aTNA) and Serinol Nucleic Acid (SNA) with Acyclic Scaffolds. Chemistry 2013; 19:14151-8. [DOI: 10.1002/chem.201301578] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Indexed: 11/08/2022]
|
167
|
De A, Souchelnytskyi S, van den Berg A, Carlen ET. Peptide nucleic acid (PNA)-DNA duplexes: comparison of hybridization affinity between vertically and horizontally tethered PNA probes. ACS APPLIED MATERIALS & INTERFACES 2013; 5:4607-4612. [PMID: 23668364 DOI: 10.1021/am4011429] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We compare the PNA-DNA duplex hybridization characteristics of vertically tethered and new horizontally tethered PNA probes on solid surfaces. The horizontal 15-mer PNA probe has been synthesized with linker molecules attached at three locations (γ-points) positioned along the PNA backbone that provides covalent attachment of the probe with the backbone aligned parallel to the surface, which is important for DNA hybridization assays that use electric field effect sensors for detection. A radioactive labeled assay and real-time surface plasmon resonance (SPR) biosensor are used to assess the probe surface density, nonspecific binding, and DNA hybridization affinity, respectively, of the new PNA probe configuration. The estimated equilibrium dissociation constants of the horizontally tethered duplex and the vertically tethered duplex are of the same order of magnitude (KD ≈ 5 nM), which indicates a sufficient hybridization affinity for many electronic biosensors that benefit from the horizontal alignment, which minimizes the effects of counterion screening.
Collapse
|
168
|
Niu Y, Wu H, Li Y, Hu Y, Padhee S, Li Q, Cao C, Cai J. AApeptides as a new class of antimicrobial agents. Org Biomol Chem 2013; 11:4283-90. [PMID: 23722277 DOI: 10.1039/c3ob40444g] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Antibiotic resistance is an increasing public health concern around the world, and is recognized as one of the greatest threats facing humankind in the 21(st) century. Natural antimicrobial peptides (AMPs) are small cationic amphiphilic peptides found in virtually all living organisms, and play a key role in the defense against bacterial infections. Compared with conventional antibiotics, which target specific metabolic processes, AMPs are able to adopt globally amphipathic conformations, and kill bacteria through disruption of their membranes. As such, AMPs do not readily induce drug-resistance. However, AMPs are associated with intrinsic drawbacks such as low-to-moderate activity, susceptibility to enzymatic degradation, and inconvenience for optimization. Recently, we have developed a new class of peptidomimetics termed "AApeptides". Such peptide mimics are highly resistant to protease degradation and are straightforward for chemical diversification and development. Our current studies show that AApeptides with globally amphipathic structures can mimic the bactericidal mechanism of AMPs, and display potent and broad-spectrum activity against both Gram-positive and -negative multi-drug-resistant bacteria. In this review, we summarize our current findings of antimicrobial AApeptides, and discuss potential future directions on the development of more potent and specific analogues.
Collapse
Affiliation(s)
- Youhong Niu
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave, Tampa, FL 33620, USA
| | | | | | | | | | | | | | | |
Collapse
|
169
|
Sadhu KK, Winssinger N. Detection of miRNA in live cells by using templated RuII-catalyzed unmasking of a fluorophore. Chemistry 2013; 19:8182-9. [PMID: 23633397 DOI: 10.1002/chem.201300060] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Indexed: 12/21/2022]
Abstract
Reactions templated by cellular nucleic acids are attractive for nucleic acid sensing or responsive systems. Herein we report the use of a photocatalyzed reductive cleavage of an immolative linker to unmask a rhodamine fluorophore, and its application to miRNA imaging. The reaction was found to proceed with a very high turnover (>4000) and provided reliable detection down to 5 pM of template by using γ-serine-modified peptide nucleic acid (PNA) probes. The reaction was used for the selective detection of miR-21 in BT474 cells and miR-31 in HeLa cells following irradiation for 30 min. The probes were introduced by using reversible permeation with streptolysin-O (SLO) or a transfection technique.
Collapse
Affiliation(s)
- Kalyan K Sadhu
- Institut de Science et Ingénierie Supramoléculaires (ISIS-UMR 7006), Université de Strasbourg, CNRS, 8 allée Gaspard Monge, 67000 Strasbourg, France
| | | |
Collapse
|
170
|
De Costa NTS, Heemstra JM. Evaluating the effect of ionic strength on duplex stability for PNA having negatively or positively charged side chains. PLoS One 2013; 8:e58670. [PMID: 23484047 PMCID: PMC3590165 DOI: 10.1371/journal.pone.0058670] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 02/06/2013] [Indexed: 11/19/2022] Open
Abstract
The enhanced thermodynamic stability of PNA:DNA and PNA:RNA duplexes compared with DNA:DNA and DNA:RNA duplexes has been attributed in part to the lack of electrostatic repulsion between the uncharged PNA backbone and negatively charged DNA or RNA backbone. However, there are no previously reported studies that systematically evaluate the effect of ionic strength on duplex stability for PNA having a charged backbone. Here we investigate the role of charge repulsion in PNA binding by synthesizing PNA strands having negatively or positively charged side chains, then measuring their duplex stability with DNA or RNA at varying salt concentrations. At low salt concentrations, positively charged PNA binds more strongly to DNA and RNA than does negatively charged PNA. However, at medium to high salt concentrations, this trend is reversed, and negatively charged PNA shows higher affinity for DNA and RNA than does positively charged PNA. These results show that charge screening by counterions in solution enables negatively charged side chains to be incorporated into the PNA backbone without reducing duplex stability with DNA and RNA. This research provides new insight into the role of electrostatics in PNA binding, and demonstrates that introduction of negatively charged side chains is not significantly detrimental to PNA binding affinity at physiological ionic strength. The ability to incorporate negative charge without sacrificing binding affinity is anticipated to enable the development of PNA therapeutics that take advantage of both the inherent benefits of PNA and the multitude of charge-based delivery technologies currently being developed for DNA and RNA.
Collapse
Affiliation(s)
- N. Tilani S. De Costa
- Department of Chemistry and the Center for Cell and Genome Science, University of Utah, Salt Lake City, Utah, United States of America
| | - Jennifer M. Heemstra
- Department of Chemistry and the Center for Cell and Genome Science, University of Utah, Salt Lake City, Utah, United States of America
| |
Collapse
|
171
|
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.
Collapse
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:
| |
Collapse
|
172
|
Gourishankar A, Ganesh KN. (α,α-dimethyl)glycyl (dmg) PNAs: achiral PNA analogs that form stronger hybrids with cDNA relative to isosequential RNA. ARTIFICIAL DNA, PNA & XNA 2012; 3:5-13. [PMID: 22679528 PMCID: PMC3368815 DOI: 10.4161/adna.19185] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The design and facile synthesis of sterically constrained new analogs of PNA having gem-dimethyl substitutions on glycine (dmg-PNA-T) is presented. The PNA oligomers [aminoethyl dimethylglycyl (aedmg) and aminopropyl dimethylglycyl (apdmg)] synthesized from the monomers 6 and 12) effected remarkable stabilization of homothyminePNA2:homoadenine DNA/RNA triplexes and mixed base sequence duplexes with target cDNA or RNA. They show a higher binding to DNA relative to that with isosequential RNA. This may be a structural consequence of the sterically rigid gem-dimethyl group, imposing a pre-organized conformation favorable for complex formation with cDNA. The results complement our previous work that had demonstrated that cyclohexanyl-PNAs favor binding with cRNA compared with cDNA and imply that the biophysical and structural properties of PNAs can be directed by introduction of the right rigidity in PNA backbone devoid of chirality. This approach of tweaking selectivity in binding of PNA constructs by installing gem-dimethyl substitution in PNA backbone can be extended to further fine-tuning by similar substitution in the aminoethyl segment as well either individually or in conjunction with present substitution.
Collapse
Affiliation(s)
- Aland Gourishankar
- Indian Institute of Science Education and Research, Division of Organic Chemistry, National Chemical Laboratory, Pune, India
| | | |
Collapse
|
173
|
Li P, Zhan C, Zhang S, Ding X, Guo F, He S, Yao J. Alkali metal cations control over nucleophilic substitutions on aromatic fused pyrimidine-2,4-[1H,3H]-diones: towards new PNA monomers. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.08.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
174
|
Recent advances in chemical modification of Peptide nucleic acids. J Nucleic Acids 2012; 2012:518162. [PMID: 22991652 PMCID: PMC3443988 DOI: 10.1155/2012/518162] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Revised: 07/12/2012] [Accepted: 07/20/2012] [Indexed: 12/14/2022] Open
Abstract
Peptide nucleic acid (PNA) has become an extremely powerful tool in chemistry and biology. Although PNA recognizes single-stranded nucleic acids with exceptionally high affinity and sequence selectivity, there is considerable ongoing effort to further improve properties of PNA for both fundamental science and practical applications. The present paper discusses selected recent studies that improve on cellular uptake and binding of PNA to double-stranded DNA and RNA. The focus is on chemical modifications of PNA's backbone and heterocyclic nucleobases. The paper selects representative recent studies and does not attempt to provide comprehensive coverage of the broad and vibrant field of PNA modification.
Collapse
|
175
|
Chouikhi D, Ciobanu M, Zambaldo C, Duplan V, Barluenga S, Winssinger N. Expanding the scope of PNA-encoded synthesis (PES): Mtt-protected PNA fully orthogonal to fmoc chemistry and a broad array of robust diversity-generating reactions. Chemistry 2012; 18:12698-704. [PMID: 22915361 DOI: 10.1002/chem.201201337] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/15/2012] [Indexed: 01/11/2023]
Abstract
Nucleic acid-encoded libraries are emerging as an attractive and highly miniaturized format for the rapid identification of protein ligands. An important criterion in the synthesis of nucleic acid encoded libraries is the scope of reactions that can be used to introduce molecular diversity and devise divergent pathways for diversity-oriented synthesis (DOS). To date, the protecting group strategies that have been used in peptide nucleic acid (PNA) encoded synthesis (PES) have limited the choice of reactions used in the library synthesis to just a few prototypes. Herein, we describe the preparation of PNA monomers with a protecting group combination (Mtt/Boc) that is orthogonal to Fmoc-based synthesis and compatible with a large palette of reactions that have been productively used in DOS (palladium cross-couplings, metathesis, reductive amination, amidation, heterocycle formation, nucleophilic addition, conjugate additions, Pictet-Spengler cyclization). We incorporate γ-modifications in the PNA backbone that are known to enhance hybridization and solubility. We demonstrate the robustness of this strategy with a library synthesis that is characterized by MALDI MS analysis at every step.
Collapse
Affiliation(s)
- Dalila Chouikhi
- Institut de Science et Ingénierie Supramoléculaires, ISIS - UMR, Université de Strasbourg - CNRS, France
| | | | | | | | | | | |
Collapse
|
176
|
Panyutin IG, Onyshchenko MI, Englund EA, Appella DH, Neumann RD. Targeting DNA G-quadruplex structures with peptide nucleic acids. Curr Pharm Des 2012; 18:1984-91. [PMID: 22376112 DOI: 10.2174/138161212799958440] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 11/28/2011] [Indexed: 11/22/2022]
Abstract
Regulation of genetic functions based on targeting DNA or RNA sequences with complementary oligonucleotides is especially attractive in the post-genome era. Oligonucleotides can be rationally designed to bind their targets based on simple nucleic acid base pairing rules. However, the use of natural DNA and RNA oligonucleotides as targeting probes can cause numerous off-target effects. In addition, natural nucleic acids are prone to degradation in vivo by various nucleases. To address these problems, nucleic acid mimics such as peptide nucleic acids (PNA) have been developed. They are more stable, show less off-target effects, and, in general, have better binding affinity to their targets. However, their high affinity to DNA can reduce their sequence-specificity. The formation of alternative DNA secondary structures, such as the G-quadruplex, provides an extra level of specificity as targets for PNA oligomers. PNA probes can target the loops of G-quadruplex, invade the core by forming PNA-DNA guanine-tetrads, or bind to the open bases on the complementary cytosine-rich strand. Not only could the development of such G-quadruplex-specific probes allow regulation of gene expression, but it will also provide a means to clarify the biological roles G-quadruplex structures may possess.
Collapse
|
177
|
Mitra R, Ganesh KN. Aminomethylene peptide nucleic acid (am-PNA): synthesis, regio-/stereospecific DNA binding, and differential cell uptake of (α/γ,R/S)am-PNA analogues. J Org Chem 2012; 77:5696-704. [PMID: 22676429 DOI: 10.1021/jo300860f] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inherently chiral, cationic am-PNAs having pendant aminomethylene groups at α(R/S) or γ(S) sites on PNA backbone have been synthesized. The modified PNAs are shown to stabilize duplexes with complementary cDNA in a regio- and stereo-preferred manner with γ(S)-am PNA superior to α(R/S)-am PNAs and α(R)-am PNA better than the α(S) isomer. The enhanced stabilization of am-PNA:DNA duplexes is accompanied by a greater discrimination of mismatched bases. This seems to be a combined result of both electrostatic interactions and conformational preorganization of backbone favoring the cDNA binding. The am-PNAs are demonstrated to effectively traverse the cell membrane, localize in the nucleus of HeLa cells, and exhibit low toxicity to cells.
Collapse
Affiliation(s)
- Roopa Mitra
- Organic Chemistry Division, National Chemical Laboratory, Pune 411008, India
| | | |
Collapse
|
178
|
Manicardi A, Fabbri E, Tedeschi T, Sforza S, Bianchi N, Brognara E, Gambari R, Marchelli R, Corradini R. Cellular uptakes, biostabilities and anti-miR-210 activities of chiral arginine-PNAs in leukaemic K562 cells. Chembiochem 2012; 13:1327-37. [PMID: 22639449 PMCID: PMC3401907 DOI: 10.1002/cbic.201100745] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Indexed: 12/11/2022]
Abstract
A series of 18-mer peptide nucleic acids (PNAs) targeted against micro-RNA miR-210 was synthesised and tested in a cellular system. Unmodified PNAs, R8-conjugated PNAs and modified PNAs containing eight arginine residues on the backbone, either as C2-modified (R) or C5-modified (S) monomers, all with the same sequence, were compared. Two different models were used for the modified PNAs: one with alternated chiral and achiral monomers and one with a stretch of chiral monomers at the N terminus. The melting temperatures of these derivatives were found to be extremely high and 5 m urea was used to assess differences between the different structures. FACS analysis and qRT-PCR on K562 chronic myelogenous leukaemic cells indicated that arginine-conjugated and backbone-modified PNAs display good cellular uptake, with best performances for the C2-modified series. Resistance to enzymatic degradation was found to be higher for the backbone-modified PNAs, thus enhancing the advantage of using these derivatives rather than conjugated PNAs in the cells in serum, and this effect is magnified in the presence of peptidases such as trypsin. Inhibition of miR-210 activity led to changes in the erythroid differentiation pathway, which were more evident in mithramycin-treated cells. Interestingly, the anti-miR activities differed with use of different PNAs, thus suggesting a role of the substituents not only in the cellular uptake, but also in the mechanism of miR recognition and inactivation. This is the first report relating to the use of backbone-modified PNAs as anti-miR agents. The results clearly indicate that backbone-modified PNAs are good candidates for the development of very efficient drugs based on anti-miR activity, due to their enhanced bioavailabilities, and that overall anti-miR performance is a combination of cellular uptake and RNA binding.
Collapse
Affiliation(s)
- Alex Manicardi
- Dipartimento di Chimica Organica e Industriale, Università di Parma, Parco Area delle Scienze 17A, 43124 Parma, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
179
|
Wierzbinski E, de Leon A, Yin X, Balaeff A, Davis KL, Reppireddy S, Venkatramani R, Keinan S, Ly DH, Madrid M, Beratan DN, Achim C, Waldeck DH. Effect of Backbone Flexibility on Charge Transfer Rates in Peptide Nucleic Acid Duplexes. J Am Chem Soc 2012; 134:9335-42. [DOI: 10.1021/ja301677z] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emil Wierzbinski
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania
15260, United States
| | - Arnie de Leon
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania
15213, United States
| | - Xing Yin
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania
15260, United States
| | - Alexander Balaeff
- Department
of Chemistry, Duke University, Durham,
North Carolina 27708, United
States
| | - Kathryn L. Davis
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania
15260, United States
| | - Srinivas Reppireddy
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania
15213, United States
| | - Ravindra Venkatramani
- Department
of Chemistry, Duke University, Durham,
North Carolina 27708, United
States
| | - Shahar Keinan
- Department
of Chemistry, Duke University, Durham,
North Carolina 27708, United
States
| | - Danith H. Ly
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania
15213, United States
| | - Marcela Madrid
- Pittsburgh Supercomputing Center, Pittsburgh, Pennsylvania 15213, United States
| | - David N. Beratan
- Departments of Chemistry, Biochemistry,
and Physics, Duke University, Durham, North
Carolina 27708, United States
| | - Catalina Achim
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania
15213, United States
| | - David H. Waldeck
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania
15260, United States
| |
Collapse
|
180
|
Avitabile C, Moggio L, Malgieri G, Capasso D, Di Gaetano S, Saviano M, Pedone C, Romanelli A. γ Sulphate PNA (PNA S): highly selective DNA binding molecule showing promising antigene activity. PLoS One 2012; 7:e35774. [PMID: 22586450 PMCID: PMC3346730 DOI: 10.1371/journal.pone.0035774] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 03/21/2012] [Indexed: 11/18/2022] Open
Abstract
Peptide Nucleic Acids (PNAs), nucleic acid analogues showing high stability to enzyme degradation and strong affinity and specificity of binding toward DNA and RNA are widely investigated as tools to interfere in gene expression. Several studies have been focused on PNA analogues with modifications on the backbone and bases in the attempt to overcome solubility, uptake and aggregation issues. γ PNAs, PNA derivatives having a substituent in the γ position of the backbone show interesting properties in terms of secondary structure and affinity of binding toward complementary nucleic acids. In this paper we illustrate our results obtained on new analogues, bearing a sulphate in the γ position of the backbone, developed to be more DNA-like in terms of polarity and charge. The synthesis of monomers and oligomers is described. NMR studies on the conformational properties of monomers and studies on the secondary structure of single strands and triplexes are reported. Furthermore the hybrid stability and the effect of mismatches on the stability have also been investigated. Finally, the ability of the new analogue to work as antigene, interfering with the transcription of the ErbB2 gene on a human cell line overexpressing ErbB2 (SKBR3), assessed by FACS and qPCR, is described.
Collapse
Affiliation(s)
- Concetta Avitabile
- Dipartimento delle Scienze Biologiche, Facoltà di Scienze Biotecnologiche, Università di Napoli “Federico II”, Napoli, Italy
| | - Loredana Moggio
- Dipartimento delle Scienze Biologiche, Facoltà di Scienze Biotecnologiche, Università di Napoli “Federico II”, Napoli, Italy
| | - Gaetano Malgieri
- Dipartimento di Scienze Ambientali, Seconda Università degli Studi di Napoli, Caserta, Italy
| | - Domenica Capasso
- Dipartimento delle Scienze Biologiche, Facoltà di Scienze Biotecnologiche, Università di Napoli “Federico II”, Napoli, Italy
| | | | | | - Carlo Pedone
- Dipartimento delle Scienze Biologiche, Facoltà di Scienze Biotecnologiche, Università di Napoli “Federico II”, Napoli, Italy
- Istituto di Biostrutture e Bioimmagini (CNR), Napoli, Italy
| | - Alessandra Romanelli
- Dipartimento delle Scienze Biologiche, Facoltà di Scienze Biotecnologiche, Università di Napoli “Federico II”, Napoli, Italy
- Istituto di Biostrutture e Bioimmagini (CNR), Napoli, Italy
- * E-mail:
| |
Collapse
|
181
|
Preparation and determination of optical purity of γ-lysine modified peptide nucleic acid analogues. Arch Pharm Res 2012; 35:517-22. [PMID: 22477199 DOI: 10.1007/s12272-012-0315-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/17/2011] [Accepted: 08/29/2011] [Indexed: 10/28/2022]
Abstract
Peptide nucleic acids (PNAs) are DNA analogues in which the nucleic acid backbone is replaced by a pseudopeptide backbone and nucleobases are attached to the backbone by methylene carbonyl linkers. γ-Carbon modification of the PNA structure allows monomers, and subsequently oligomers, with improved properties to be obtained. In this study, we report the convenient synthesis of γ-lysine-modified PNA monomers for pyrimidine bases (thymine and cytosine) with high optical purity (> 99.5%) and direct enantiomer separation of γ-lysine-modified PNA analogs, using chiral HPLC to determine the optical purity.
Collapse
|
182
|
Totsingan F, Jain V, Green MM. Helix control in polymers: case of peptide nucleic acids (PNAs). ARTIFICIAL DNA, PNA & XNA 2012; 3:31-44. [PMID: 22772039 PMCID: PMC3429529 DOI: 10.4161/adna.20572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The helix is a critical conformation exhibited by biological macromolecules and plays a key role in fundamental biological processes. Biological helical polymers exist in a single helical sense arising from the chiral effect of their primary units-for example, DNA and proteins adopt predominantly a right-handed helix conformation in response to the asymmetric conformational propensity of D-sugars and L-amino acids, respectively. In using these homochiral systems, nature blocks our observations of some fascinating aspects of the cooperativity in helical systems, although when useful for a specific purpose, "wrong" enantiomers may be incorporated in specific places. In synthetic helical systems, on the contrary, incorporation of non-racemic chirality is an additional burden, and the findings discussed in this review show that this burden may be considerably alleviated by taking advantage of the amplification of chirality, in which small chiral influences lead to large consequences. Peptide nucleic acid (PNA), which is a non-chiral synthetic DNA mimic, shows a cooperative response to a small chiral effect induced by a chiral amino acid, which is limited, however, due to the highly flexible nature of this oligomeric chimera. The lack of internal stereochemical bias is an important factor which makes PNA an ideal system to understand some cooperative features that are not directly accessible from DNA.
Collapse
|
183
|
Manicardi A, Accetta A, Tedeschi T, Sforza S, Marchelli R, Corradini R. PNA bearing 5-azidomethyluracil: a novel approach for solid and solution phase modification. ARTIFICIAL DNA, PNA & XNA 2012; 3:53-62. [PMID: 22772040 PMCID: PMC3429531 DOI: 10.4161/adna.20158] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fmoc- and Boc-protected modified monomers bearing 5-azidomethyluracil nucleobase were synthesized. Four different solid-phase synthetic strategies were tested in order to evaluate the application of this series of monomers for the solid-phase synthesis of modified PNA. The azide was used as masked amine for the introduction of amide-linked functional groups, allowing the production of a library of compounds starting from a single modified monomer. The azide function was also exploited as reactive group for the modification of PNA in solution via azide-alkyne click cycloaddition.
Collapse
Affiliation(s)
- Alex Manicardi
- Dipartimento di Chimica Organica e Industriale, Università di Parma, Parma, Italy.
| | | | | | | | | | | |
Collapse
|
184
|
Rapireddy S, Nhon L, Meehan RE, Franks J, Stolz DB, Tran D, Selsted ME, Ly DH. RTD-1mimic containing γPNA scaffold exhibits broad-spectrum antibacterial activities. J Am Chem Soc 2012; 134:4041-4. [PMID: 22332599 PMCID: PMC4848027 DOI: 10.1021/ja211867j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Macrocyclic peptides with multiple disulfide cross-linkages, such as those produced by plants and those found in nonhuman primates, as components of the innate immunity, hold great promise for molecular therapy because of their broad biological activities and high chemical, thermal, and enzymatic stability. However, for some, because of their intricate spatial arrangement and elaborate interstrand cross-linkages, they are difficult to prepare de novo in large quantities and high purity, due to the nonselective nature of disulfide-bond formation. We show that the disulfide bridges of RTD-1, a member of the θ-defensin subfamily, could be replaced with noncovalent Watson-Crick hydrogen bonds without significantly affecting its biological activities. The work provides a general strategy for engineering conformationally rigid, cyclic peptides without the need for disulfide-bond reinforcement.
Collapse
Affiliation(s)
- Srinivas Rapireddy
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Linda Nhon
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Robert E. Meehan
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Jonathan Franks
- Department of Cell Biology & Physiology, University of Pittsburgh School of Medicine, S362 BST, 3500 Terrace Street, Pittsburgh, PA 15261
| | - Donna Beer Stolz
- Department of Cell Biology & Physiology, University of Pittsburgh School of Medicine, S362 BST, 3500 Terrace Street, Pittsburgh, PA 15261
| | - Dat Tran
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Michael E. Selsted
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Danith H. Ly
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| |
Collapse
|
185
|
Mansawat W, Vilaivan C, Balázs Á, Aitken DJ, Vilaivan T. Pyrrolidinyl peptide nucleic acid homologues: effect of ring size on hybridization properties. Org Lett 2012; 14:1440-3. [PMID: 22375845 DOI: 10.1021/ol300190u] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effect of ring size of four- to six-membered cyclic β-amino acid on the hybridization properties of pyrrolidinyl peptide nucleic acid with an alternating α/β peptide backbone is reported. The cyclobutane derivatives (acbcPNA) show the highest T(m) and excellent specificity with cDNA and RNA.
Collapse
Affiliation(s)
- Woraluk Mansawat
- Organic Synthesis Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330, Thailand
| | | | | | | | | |
Collapse
|
186
|
Abstract
The increasing sensitivity of PCR has meant that in the last two decades PCR has emerged as a major tool in diet studies, enabling us to refine our understanding of trophic links and to elucidate the diets of predators whose prey is as yet uncharacterized. The achievements and methods of PCR-based diet studies have been reviewed several times, but here we review an important development in the field: the use of PCR enrichment techniques to promote the amplification of prey DNA over that of the predator. We first discuss the success of using group-specific primers either in parallel single reactions or in multiplex reactions. We then concentrate on the more recent use of PCR enrichment techniques such as restriction enzyme digests, peptide nucleic acid clamping, DNA blocking and laser capture microdissection. We also survey the vast literature on enrichment techniques in clinical biology, to ascertain the pitfalls of enrichment techniques and what refinements have yielded some highly sensitive methods. We find that while there are several new approaches to enrichment, peptide nucleic acid clamping and DNA blocking are generally sufficient techniques for the characterization of diets of predators and highlight the most important considerations of the approach.
Collapse
Affiliation(s)
- R O'Rorke
- Leigh Marine Laboratory, University of Auckland, Warkworth, Northland 0941, New Zealand.
| | | | | |
Collapse
|
187
|
Bezer S, Rapireddy S, Skorik YA, Ly DH, Achim C. Coordination-driven inversion of handedness in ligand-modified PNA. Inorg Chem 2011; 50:11929-37. [PMID: 22059624 DOI: 10.1021/ic200855p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptide nucleic acid (PNA) is a synthetic analogue of DNA, which has the same nucleobases as DNA but typically has a backbone based on aminoethyl glycine (Aeg). PNA forms duplexes by Watson Crick hybridization. The Aeg-based PNA duplexes adopt a chiral helical structure but do not have a preferred handedness because they do not contain a chiral center. An L-lysine situated at the C-end of one or both strands of a PNA duplex causes the duplex to preferably adopt a left-handed structure. We have introduced into the PNA duplexes both a C-terminal L-lysine and one or two PNA monomers that have a γ-(S)-methyl-aminoethyl glycine backbone, which is known to induce a preference for a right-handed structure. Indeed, we found that in these duplexes the γ-methyl monomer exerts the dominant chiral induction effect causing the duplexes to adopt a right-handed structure. The chiral PNA monomer had a 2,2':6',2''-terpyridine (Tpy) ligand instead of a nucleobase and PNA duplexes that contained one or two Tpys formed [Cu(Tpy)(2)](2+) complexes in the presence of Cu(2+). The CD spectroscopy studies showed that these metal-coordinated duplexes were right-handed due to the chiral induction effect exerted by the S-Tpy PNA monomer(s) except for the cases when the [Cu(Tpy)(2)](2+) complex was formed with Tpy ligands from two different PNA duplexes. In the latter case, the metal complex bridged the two PNA duplexes and the duplexes were left-handed. The results of this study show that the preferred handedness of a ligand-modified PNA can be switched as a consequence of metal coordination to the ligand. This finding could be used as a tool in the design of functional nucleic-acid based nanostructures.
Collapse
Affiliation(s)
- Silvia Bezer
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213-3890, USA
| | | | | | | | | |
Collapse
|
188
|
Imaging of RNA in live cells. Curr Opin Chem Biol 2011; 15:806-12. [PMID: 22055496 DOI: 10.1016/j.cbpa.2011.10.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 10/11/2011] [Accepted: 10/17/2011] [Indexed: 01/07/2023]
Abstract
Fluorescence microscopy and molecular tagging technologies have ushered in a new era in our understanding of protein localization and function in cells. This review summarizes recent efforts to extend some of these methods (and to create new ones) to imaging of RNA in live cells. Both fluorescent proteins and hybridization probes allow noncovalent labeling of specific RNA molecules with fluorescent dyes that allow detection and tracking in real time.
Collapse
|
189
|
β-PNA: peptide nucleic acid (PNA) with a chiral center at the β-position of the PNA backbone. Bioorg Med Chem Lett 2011; 21:7317-20. [PMID: 22050888 DOI: 10.1016/j.bmcl.2011.10.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 10/04/2011] [Accepted: 10/07/2011] [Indexed: 11/22/2022]
Abstract
Peptide nucleic acid (PNA) monomers with a methyl group at the β-position have been synthesized. The modified monomers were incorporated into PNA oligomers using Fmoc chemistry for solid-phase synthesis. Thermal denaturation and circular dichroism (CD) studies have shown that PNA containing the S-form monomers was well suited to form a hybrid duplex with DNA, whose stability was comparable to that of unmodified PNA-DNA duplex, whereas PNA containing the R-form monomers was not.
Collapse
|
190
|
Sahu B, Sacui I, Rapireddy S, Zanotti KJ, Bahal R, Armitage BA, Ly DH. Synthesis and characterization of conformationally preorganized, (R)-diethylene glycol-containing γ-peptide nucleic acids with superior hybridization properties and water solubility. J Org Chem 2011; 76:5614-27. [PMID: 21619025 PMCID: PMC3175361 DOI: 10.1021/jo200482d] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Developed in the early 1990s, peptide nucleic acid (PNA) has emerged as a promising class of nucleic acid mimic because of its strong binding affinity and sequence selectivity toward DNA and RNA and resistance to enzymatic degradation by proteases and nucleases; however, the main drawbacks, as compared to other classes of oligonucleotides, are water solubility and biocompatibility. Herein we show that installation of a relatively small, hydrophilic (R)-diethylene glycol ("miniPEG", R-MP) unit at the γ-backbone transforms a randomly folded PNA into a right-handed helix. Synthesis of optically pure (R-MP)γPNA monomers is described, which can be accomplished in a few simple steps from a commercially available and relatively cheap Boc-l-serine. Once synthesized, (R-MP)γPNA oligomers are preorganized into a right-handed helix, hybridize to DNA and RNA with greater affinity and sequence selectivity, and are more water soluble and less aggregating than the parental PNA oligomers. The results presented herein have important implications for the future design and application of PNA in biology, biotechnology, and medicine, as well as in other disciplines, including drug discovery and molecular engineering.
Collapse
Affiliation(s)
- Bichismita Sahu
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Iulia Sacui
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Srinivas Rapireddy
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Kimberly J. Zanotti
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Raman Bahal
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Bruce A. Armitage
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Danith H. Ly
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| |
Collapse
|
191
|
Crawford MJ, Rapireddy S, Bahal R, Sacui I, Ly DH. Effect of Steric Constraint at the γ-Backbone Position on the Conformations and Hybridization Properties of PNAs. J Nucleic Acids 2011; 2011:652702. [PMID: 21776375 PMCID: PMC3138043 DOI: 10.4061/2011/652702] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 01/06/2011] [Accepted: 03/14/2011] [Indexed: 11/30/2022] Open
Abstract
Conformationally preorganized peptide nucleic acids (PNAs) have been synthesized through backbone modifications at the γ-position, where R = alanine, valine, isoleucine, and phenylalanine side chains. The effects of these side-chains on the conformations and hybridization properties of PNAs were determined using a combination of CD and UV-Vis spectroscopic techniques. Our results show that the γ-position can accommodate varying degrees of sterically hindered side-chains, reaffirming the bimodal function of PNAs as the true hybrids of “peptides” and “nucleic acids.”
Collapse
Affiliation(s)
- Matthew J Crawford
- Department of Chemistry, Center for Nucleic Acids Science and Technology (CNAST), Mellon Institute, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | | | | | | | | |
Collapse
|
192
|
Rapireddy S, Bahal R, Ly DH. Strand invasion of mixed-sequence, double-helical B-DNA by γ-peptide nucleic acids containing G-clamp nucleobases under physiological conditions. Biochemistry 2011; 50:3913-8. [PMID: 21476606 PMCID: PMC3092786 DOI: 10.1021/bi2002554] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptide nucleic acids (PNAs) make up the only class of nucleic acid mimics developed to date that has been shown to be capable of invading double-helical B-form DNA. Recently, we showed that sequence limitation associated with PNA recognition can be relaxed by utilizing conformationally preorganized γ-peptide nucleic acids (γPNAs). However, like all the previous studies, with the exception of triplex binding, DNA strand invasion was performed at relatively low salt concentrations. When physiological ionic strengths were used, little to no binding was observed. On the basis of this finding, it was not clear whether the lack of binding is due to the lack of base pair opening or the lack of binding free energy, either of which would result in no productive binding. In this work, we show that it is the latter. Under simulated physiological conditions, the DNA double helix is sufficiently dynamic to permit strand invasion by the designer oligonucleotide molecules provided that the required binding free energy can be met. This finding has important implications for the design oligonucleotides for recognition of B-DNA via direct Watson-Crick base pairing.
Collapse
Affiliation(s)
- Srinivas Rapireddy
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA
| | - Raman Bahal
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA
| | - Danith H. Ly
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA
| |
Collapse
|
193
|
Manicardi A, Calabretta A, Bencivenni M, Tedeschi T, Sforza S, Corradini R, Marchelli R. Affinity and selectivity of C2- and C5-substituted "chiral-box" PNA in solution and on microarrays. Chirality 2011; 22 Suppl 1:E161-72. [PMID: 21038387 DOI: 10.1002/chir.20865] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Two peptide nucleic acids (PNAs) containing three adjacent modified chiral monomers (chiral box) were synthesized. The chiral monomers contained either a C2- or a C5-modified backbone, synthesized starting from D- and L-arginine, respectively (2D- and 5L-PNA). The C2-modified chiral PNA was synthesized using a submonomeric strategy to avoid epimerization during solid-phase synthesis, whereas for the C5-derivative, the monomers were first obtained and then used in solid-phase synthesis. The melting temperature of these PNA duplexes formed with the full-match or with single-mismatch DNA were measured both by UV and by CD spectroscopy and compared with the unmodified PNA. The 5L-chiral-box-PNA showed the highest T(m) with full-match DNA, whereas the 2D-chiral-box-PNA showed the highest sequence selectivity. The PNA were spotted on microarray slides and then hybridized with Cy5-labeled full match and mismatched oligonucleotides. The results obtained showed a signal intensity in the order achiral >2D-chiral box >5L-chiral box, whereas the full-match/mismatch selectivity was higher for the 2D chiral box PNA.
Collapse
Affiliation(s)
- Alex Manicardi
- Dipartimento di Chimica Organica e Industriale Università di Parma, 43100 Parma, Italy
| | | | | | | | | | | | | |
Collapse
|
194
|
Hu Y, Li X, Sebti SM, Chen J, Cai J. Design and synthesis of AApeptides: a new class of peptide mimics. Bioorg Med Chem Lett 2011; 21:1469-71. [PMID: 21292484 DOI: 10.1016/j.bmcl.2011.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 12/24/2010] [Accepted: 01/03/2011] [Indexed: 10/18/2022]
Abstract
A new family of peptide mimics termed 'AApeptides', which are oligomers of N-acylated-N-aminoethyl amino acids, was proposed. The design and efficient synthesis of AApeptides are described. As proof-of-the-concept, we show that AApeptides can inhibit p53/MDM2 protein-protein interaction with significant activity (IC(50)=38 μM) and specificity. Preliminary data also demonstrates that AApeptides are resistant to enzymatic hydrolysis. With the ease of synthesis and diversification, potent bioactivity, and resistance to proteolysis, the development of sequence-specific AApeptides may expand the potential biomedical applications of peptidomimetics.
Collapse
Affiliation(s)
- Yaogang Hu
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
| | | | | | | | | |
Collapse
|
195
|
|
196
|
Panecka J, Mura C, Trylska J. Molecular dynamics of potential rRNA binders: single-stranded nucleic acids and some analogues. J Phys Chem B 2010; 115:532-46. [PMID: 21192664 DOI: 10.1021/jp106404u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
By hindering or "silencing" protein translation in vivo, antisense nucleic acid analogues that hybridize to bacterial rRNA could serve as a promising class of antibacterial compounds. Thus, we performed a comparative analysis of the dynamical properties of modified oligonucleotides based upon a sequence (5')r(UGUUACGACU)(3') that is complementary to bacterial ribosomal A-site RNA. In particular, 25 ns explicit solvent molecular dynamics simulations were computed for the following six single-stranded decamers: (1) the above RNA in unmodified form; (2) the 2'-O-methyl-modified RNA; (3) peptide nucleic acid (PNA) analogues of the above sequence, containing either (a) T or (b) U; and (4) two serine-substituted PNAs. Our results show that 2'-O-methylation attenuates RNA backbone dynamics, thereby preventing interconversion between stacked and unstacked conformations. The PNA analogue is rendered less flexible by replacing uracil with thymine; in addition, we found that derivatizing the PNA backbone with serine leads to enhanced base-stacking interactions. Consistent with known solubility properties of these classes of molecules, both RNAs exhibited greater localization of water molecules than did PNA. In terms of counterions, the initially helical conformation of the 2'-O-methyl RNA exhibits the highest Na(+) density among all the simulated decamers, while Na(+) build-up was most negligible for the neutral PNA systems. Further studies of the conformational and physicochemical properties of such modified single-stranded oligomers may facilitate better design of nucleic acid analogues, particularly those capable of serving as specific, high-affinity ribosomal A-site binders.
Collapse
Affiliation(s)
- Joanna Panecka
- Department of Biophysics, Institute of Experimental Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | | | | |
Collapse
|
197
|
Pensato S, Saviano M, Bianchi N, Borgatti M, Fabbri E, Gambari R, Romanelli A. gamma-Hydroxymethyl PNAs: Synthesis, interaction with DNA and inhibition of protein/DNA interactions. Bioorg Chem 2010; 38:196-201. [PMID: 20643471 DOI: 10.1016/j.bioorg.2010.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 06/22/2010] [Accepted: 06/25/2010] [Indexed: 10/19/2022]
Abstract
The ability of PNA to interact with DNA double stranded has been recently investigated. In a decoy approach these interactions are of great importance as may lead to inhibition of interactions of DNA sequences to specific transcription factors and may be employed as a strategy for the inhibition of gene transcription alternative to the antisense strategy (targeting transcription factors mRNAs) and the transcription factor decoy approach (targeting transcription factors). We explored the ability of PNA and PNAs with modified monomers to bind to DNA and to interfere in the formation of DNA/transcription factor complex. We report a procedure for the synthesis of Fmoc-gamma-hydroxymetyl PNA, the synthesis and CD analysis of PNA oligomers containing the modified monomer in different positions and EMSA assays to test the: (a) binding to double stranded DNA and (b) inhibition of DNA-protein interactions.
Collapse
|
198
|
Mitra R, Ganesh KN. PNAs grafted with (α/γ, R/S)-aminomethylene pendants: regio and stereo specific effects on DNA binding and improved cell uptake. Chem Commun (Camb) 2010; 47:1198-200. [PMID: 21107493 DOI: 10.1039/c0cc03988h] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PNAs grafted with cationic aminomethylene (am) pendants on the backbone at the glycyl (α) or ethylenediamine (γ) segments show regio (α/γ) and stereochemistry (R/S) dependent binding with complementary DNA. These are efficiently taken up by cells, with γ(S-am) aeg-PNA being the best in all properties.
Collapse
Affiliation(s)
- Roopa Mitra
- Division of Organic Chemistry, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008, India
| | | |
Collapse
|
199
|
Yeh JI, Shivachev B, Rapireddy S, Crawford MJ, Gil RR, Du S, Madrid M, Ly DH. Crystal structure of chiral gammaPNA with complementary DNA strand: insights into the stability and specificity of recognition and conformational preorganization. J Am Chem Soc 2010; 132:10717-27. [PMID: 20681704 DOI: 10.1021/ja907225d] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have determined the structure of a PNA-DNA duplex to 1.7 A resolution by multiple-wavelength anomalous diffraction phasing method on a zinc derivative. This structure represents the first high-resolution 3D view of a hybrid duplex containing a contiguous chiral PNA strand with complete gamma-backbone modification ("gammaPNA"). Unlike the achiral counterpart, which adopts a random-fold, this particular gammaPNA is already preorganized into a right-handed helix as a single strand. The new structure illustrates the unique characteristics of this modified PNA, possessing conformational flexibility while maintaining sufficient structural integrity to ultimately adopt the preferred P-helical conformation upon hybridization with DNA. The unusual structural adaptability found in the gammaPNA strand is crucial for enabling the accommodation of backbone modifications while constraining conformational states. In conjunction with NMR analysis characterizing the structures and substructures of the individual building blocks, these results provide unprecedented insights into how this new class of chiral gammaPNA is preorganized and stabilized, before and after hybridization with a cDNA strand. Such knowledge is crucial for the future design and development of PNA for applications in biology, biotechnology, and medicine.
Collapse
Affiliation(s)
- Joanne I Yeh
- Department of Structural Biology, University of Pittsburgh Medical School 1036 BST3, 3501 Fifth Avenue, Pittsburgh, Pennsylvania 15260, USA.
| | | | | | | | | | | | | | | |
Collapse
|
200
|
DNA-, RNA- and self-pairing properties of a pyrrolidinyl peptide nucleic acid with a (2′R,4′S)-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid backbone. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.08.102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|