1
|
Pallan PS, Lybrand TP, Rozners E, Abramov M, Schepers G, Eremeeva E, Herdewijn P, Egli M. Conformational Morphing by a DNA Analogue Featuring 7-Deazapurines and 5-Halogenpyrimidines and the Origins of Adenine-Tract Geometry. Biochemistry 2023; 62:2854-2867. [PMID: 37694722 PMCID: PMC11062489 DOI: 10.1021/acs.biochem.3c00327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Several efforts are currently directed at the creation and cellular implementation of alternative genetic systems composed of pairing components that are orthogonal to the natural dA/dT and dG/dC base pairs. In an alternative approach, Watson-Crick-type pairing is conserved, but one or all of the four letters of the A, C, G, and T alphabet are substituted by modified components. Thus, all four nucleobases were altered to create halogenated deazanucleic acid (DZA): dA was replaced by 7-deaza-2'-deoxyadenosine (dzA), dG by 7-deaza-2'-deoxyguanosine (dzG), dC by 5-fluoro-2'-deoxycytidine (FdC), and dT by 5-chloro-2'-deoxyuridine (CldU). This base-pairing system was previously shown to retain function in Escherichia coli. Here, we analyze the stability, hydration, structure, and dynamics of a DZA Dickerson-Drew Dodecamer (DDD) of sequence 5'-FdC-dzG-FdC-dzG-dzA-dzA-CldU-CldU-FdC-dzG-FdC-dzG-3'. Contrary to similar stabilities of DDD and DZA-DDD, osmotic stressing revealed a dramatic loss of hydration for the DZA-DDD relative to that for the DDD. The parent DDD 5'-d(CGCGAATTCGCG)-3' features an A-tract, a run of adenosines uninterrupted by a TpA step, and exhibits a hallmark narrow minor groove. Crystal structures─in the presence of RNase H─and MD simulations show increased conformational plasticity ("morphing") of DZA-DDD relative to that of the DDD. The narrow dzA-tract minor groove in one structure widens to resemble that in canonical B-DNA in a second structure. These changes reflect an indirect consequence of altered DZA major groove electrostatics (less negatively polarized compared to that in DNA) and hydration (reduced compared to that in DNA). Therefore, chemical modifications outside the minor groove that lead to collapse of major groove electrostatics and hydration can modulate A-tract geometry.
Collapse
Affiliation(s)
- Pradeep S Pallan
- School of Medicine, Department of Biochemistry, and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Terry P Lybrand
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Eriks Rozners
- Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States
| | - Mikhail Abramov
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Guy Schepers
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Elena Eremeeva
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Piet Herdewijn
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Martin Egli
- School of Medicine, Department of Biochemistry, and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| |
Collapse
|
2
|
Egli M, Schlegel MK, Manoharan M. Acyclic ( S)-glycol nucleic acid ( S-GNA) modification of siRNAs improves the safety of RNAi therapeutics while maintaining potency. RNA (NEW YORK, N.Y.) 2023; 29:402-414. [PMID: 36725319 PMCID: PMC10019370 DOI: 10.1261/rna.079526.122] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Glycol nucleic acid (GNA) is an acyclic nucleic acid analog connected via phosphodiester bonds. Crystal structures of RNA-GNA chimeric duplexes indicated that nucleotides of the right-handed (S)-GNA were better accommodated in the right-handed RNA duplex than were the left-handed (R)-isomers. GNA nucleotides adopt a rotated nucleobase orientation within all duplex contexts, pairing with complementary RNA in a reverse Watson-Crick mode, which explains the inabilities of GNA C and G to form strong base pairs with complementary nucleotides. Transposition of the hydrogen bond donor and acceptor pairs using novel (S)-GNA isocytidine and isoguanosine nucleotides resulted in stable base-pairing with the complementary G and C ribonucleotides, respectively. GNA nucleotide or dinucleotide incorporation into an oligonucleotide increased resistance against 3'-exonuclease-mediated degradation. Consistent with the structural observations, small interfering RNAs (siRNAs) modified with (S)-GNA had greater in vitro potencies than identical sequences containing (R)-GNA. (S)-GNA is well tolerated in the seed regions of antisense and sense strands of a GalNAc-conjugated siRNA in vitro. The siRNAs containing a GNA base pair in the seed region had in vivo potency when subcutaneously injected into mice. Importantly, seed pairing destabilization resulting from a single GNA nucleotide at position 7 of the antisense strand mitigated RNAi-mediated off-target effects in a rodent model. Two GNA-modified siRNAs have shown an improved safety profile in humans compared with their non-GNA-modified counterparts, and several additional siRNAs containing the GNA modification are currently in clinical development.
Collapse
Affiliation(s)
- Martin Egli
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Mark K Schlegel
- Alnylam Pharmaceuticals, Inc., Cambridge, Massachusetts 02142, USA
| | | |
Collapse
|
3
|
Schlegel MK, Matsuda S, Brown CR, Harp JM, Barry JD, Berman D, Castoreno A, Schofield S, Szeto J, Manoharan M, Charissé K, Egli M, Maier MA. Overcoming GNA/RNA base-pairing limitations using isonucleotides improves the pharmacodynamic activity of ESC+ GalNAc-siRNAs. Nucleic Acids Res 2021; 49:10851-10867. [PMID: 34648028 PMCID: PMC8565336 DOI: 10.1093/nar/gkab916] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 09/19/2021] [Accepted: 09/27/2021] [Indexed: 11/30/2022] Open
Abstract
We recently reported that RNAi-mediated off-target effects are important drivers of the hepatotoxicity observed for a subset of GalNAc–siRNA conjugates in rodents, and that these findings could be mitigated by seed-pairing destabilization using a single GNA nucleotide placed within the seed region of the guide strand. Here, we report further investigation of the unique and poorly understood GNA/RNA cross-pairing behavior to better inform GNA-containing siRNA design. A reexamination of published GNA homoduplex crystal structures, along with a novel structure containing a single (S)-GNA-A residue in duplex RNA, indicated that GNA nucleotides universally adopt a rotated nucleobase orientation within all duplex contexts. Such an orientation strongly affects GNA-C and GNA-G but not GNA-A or GNA-T pairing in GNA/RNA heteroduplexes. Transposition of the hydrogen-bond donor/acceptor pairs using the novel (S)-GNA-isocytidine and -isoguanosine nucleotides could rescue productive base-pairing with the complementary G or C ribonucleotides, respectively. GalNAc-siRNAs containing these GNA isonucleotides showed an improved in vitro activity, a similar improvement in off-target profile, and maintained in vivo activity and guide strand liver levels more consistent with the parent siRNAs than those modified with isomeric GNA-C or -G, thereby expanding our toolbox for the design of siRNAs with minimized off-target activity.
Collapse
Affiliation(s)
| | | | | | - Joel M Harp
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | | | - Daniel Berman
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - John Szeto
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - Martin Egli
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | | |
Collapse
|
4
|
Berlyoung AS, Armitage BA. Assembly and Characterization of RNA/DNA Hetero-G-Quadruplexes. Biochemistry 2020; 59:4072-4080. [PMID: 33048532 DOI: 10.1021/acs.biochem.0c00657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transient association of guanine-rich RNA and DNA in the form of hetero-G-quadruplexes (RDQs) has emerged as an important mechanism for regulating genome transcription and replication but relatively little is known about the structure and biophysical properties of RDQs compared with DNA and RNA homo-G-quadruplexes. Herein, we report the assembly and characterization of three RDQs based on sequence motifs found in human telomeres and mitochondrial nucleic acids. Stable RDQs were assembled using a duplex scaffold, which prevented segregation of the DNA and RNA strands into separate homo-GQs. Each of the RDQs exhibited UV melting temperatures above 50 °C in 100 mM KCl and predominantly parallel morphologies, evidently driven by the RNA component. The fluorogenic dye thioflavin T binds to each RDQ with low micromolar KD values, similar to its binding to RNA and DNA homo-GQs. These results establish a method for assembling RDQs that should be amenable to screening compounds and libraries to identify selective RDQ-binding small molecules, oligonucleotides, and proteins.
Collapse
Affiliation(s)
- April S Berlyoung
- Department of Chemistry and Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Bruce A Armitage
- Department of Chemistry and Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
5
|
Khan SI, Ali Khan I, Badshah A, Perveen Malik F, Tabassum S, Ullah I, Zargarian D, Khawar Rauf M. Mononuclear copper(I) complexes with triphenylphosphine and N,N′-disubstituted thioureas: synthesis, characterization, and biological evaluation. J COORD CHEM 2018. [DOI: 10.1080/00958972.2018.1538504] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Syed Ishtiaq Khan
- Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan
| | - Inayat Ali Khan
- Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan
- Al-Farabi Research Complex, SA-Center for Interdisciplinary Research in Basic Sciences, International Islamic University (IIU), Islamabad, Pakistan
| | - Amin Badshah
- Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan
| | - Fouzia Perveen Malik
- Research Center for Modeling and Simulations, National University of Science Technology (NUST), Islamabad, Pakistan
| | - Saira Tabassum
- Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Ikram Ullah
- Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Davit Zargarian
- Department of Chemistry, University of the Montreal, Montréal, Québec, Canada
| | | |
Collapse
|
6
|
Probst M, Aeschimann W, Chau TTH, Langenegger SM, Stocker A, Häner R. Structural insight into DNA-assembled oligochromophores: crystallographic analysis of pyrene- and phenanthrene-modified DNA in complex with BpuJI endonuclease. Nucleic Acids Res 2016; 44:7079-89. [PMID: 27422870 PMCID: PMC5009758 DOI: 10.1093/nar/gkw644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 01/13/2023] Open
Abstract
The use of the DNA duplex as a supramolecular scaffold is an established approach for the assembly of chromophore aggregates. In the absence of detailed structural insight, the characterization of thus assembled oligochromophores is, today, largely based on solution-phase spectroscopy. Here, we describe the crystal structures of three DNA-organized chromophore aggregates. DNA hybrids containing non-nucleosidic pyrene and phenanthrene building blocks were co-crystallized with the recently described binding domain of the restriction enzyme BpuJI. Crystal structures of these complexes were determined at 2.7, 1.9 and 1.6 Å resolutions. The structures reveal aromatic stacking interactions between pyrene and/or phenanthrene units within the framework of the B-DNA duplex. In hybrids containing a single modification in each DNA strand near the end of the duplex, the two polyaromatic hydrocarbons are engaged in a face-to-face stacking orientation. Due to crystal packing and steric effects, the terminal GC base pair is disrupted in all three crystal structures, which results in a non-perfect stacking arrangement of the aromatic chromophores in two of the structures. In a hybrid containing a total of three pyrenes, crystal lattice induced end-to-end stacking of individual DNA duplexes leads to the formation of an extended aromatic π-stack containing four co-axially arranged pyrenes. The aromatic planes of the stacked pyrenes are oriented in a parallel way. The study demonstrates the value of co-crystallization of chemically modified DNA with the recombinant binding domain of the restriction enzyme BpuJI for obtaining detailed structural insight into DNA-assembled oligochromophores.
Collapse
Affiliation(s)
- Markus Probst
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Walter Aeschimann
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Thi T H Chau
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Simon M Langenegger
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Achim Stocker
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Robert Häner
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| |
Collapse
|
7
|
Anosova I, Kowal EA, Dunn MR, Chaput JC, Van Horn WD, Egli M. The structural diversity of artificial genetic polymers. Nucleic Acids Res 2015; 44:1007-21. [PMID: 26673703 PMCID: PMC4756832 DOI: 10.1093/nar/gkv1472] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 11/30/2015] [Indexed: 11/13/2022] Open
Abstract
Synthetic genetics is a subdiscipline of synthetic biology that aims to develop artificial genetic polymers (also referred to as xeno-nucleic acids or XNAs) that can replicate in vitro and eventually in model cellular organisms. This field of science combines organic chemistry with polymerase engineering to create alternative forms of DNA that can store genetic information and evolve in response to external stimuli. Practitioners of synthetic genetics postulate that XNA could be used to safeguard synthetic biology organisms by storing genetic information in orthogonal chromosomes. XNA polymers are also under active investigation as a source of nuclease resistant affinity reagents (aptamers) and catalysts (xenozymes) with practical applications in disease diagnosis and treatment. In this review, we provide a structural perspective on known antiparallel duplex structures in which at least one strand of the Watson-Crick duplex is composed entirely of XNA. Currently, only a handful of XNA structures have been archived in the Protein Data Bank as compared to the more than 100 000 structures that are now available. Given the growing interest in xenobiology projects, we chose to compare the structural features of XNA polymers and discuss their potential to access new regions of nucleic acid fold space.
Collapse
Affiliation(s)
- Irina Anosova
- The Biodesign Institute, Virginia G. Piper Center for Personalized Diagnostics, School of Molecular Sciences, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-5001, USA
| | - Ewa A Kowal
- Department of Biochemistry, Center for Structural Biology, and Vanderbilt Ingram Cancer Center, Vanderbilt University, School of Medicine, Nashville, TN 37232-0146, USA
| | - Matthew R Dunn
- Department of Pharmaceutical Sciences, University of California-Irvine, Irvine, CA 92697, USA
| | - John C Chaput
- Department of Pharmaceutical Sciences, University of California-Irvine, Irvine, CA 92697, USA
| | - Wade D Van Horn
- The Biodesign Institute, Virginia G. Piper Center for Personalized Diagnostics, School of Molecular Sciences, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-5001, USA
| | - Martin Egli
- Department of Biochemistry, Center for Structural Biology, and Vanderbilt Ingram Cancer Center, Vanderbilt University, School of Medicine, Nashville, TN 37232-0146, USA
| |
Collapse
|
8
|
Ding Y, Zhang X, Tham KW, Qin PZ. Experimental mapping of DNA duplex shape enabled by global lineshape analyses of a nucleotide-independent nitroxide probe. Nucleic Acids Res 2014; 42:e140. [PMID: 25092920 PMCID: PMC4191381 DOI: 10.1093/nar/gku695] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Sequence-dependent variation in structure and dynamics of a DNA duplex, collectively referred to as ‘DNA shape’, critically impacts interactions between DNA and proteins. Here, a method based on the technique of site-directed spin labeling was developed to experimentally map shapes of two DNA duplexes that contain response elements of the p53 tumor suppressor. An R5a nitroxide spin label, which was covalently attached at a specific phosphate group, was scanned consecutively through the DNA duplex. X-band continuous-wave electron paramagnetic resonance spectroscopy was used to monitor rotational motions of R5a, which report on DNA structure and dynamics at the labeling site. An approach based on Pearson's coefficient analysis was developed to collectively examine the degree of similarity among the ensemble of R5a spectra. The resulting Pearson's coefficients were used to generate maps representing variation of R5a mobility along the DNA duplex. The R5a mobility maps were found to correlate with maps of certain DNA helical parameters, and were capable of revealing similarity and deviation in the shape of the two closely related DNA duplexes. Collectively, the R5a probe and the Pearson's coefficient-based lineshape analysis scheme yielded a generalizable method for examining sequence-dependent DNA shapes.
Collapse
Affiliation(s)
- Yuan Ding
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Xiaojun Zhang
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Kenneth W Tham
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Peter Z Qin
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| |
Collapse
|
9
|
Zhang X, Dantas Machado AC, Ding Y, Chen Y, Lu Y, Duan Y, Tham KW, Chen L, Rohs R, Qin PZ. Conformations of p53 response elements in solution deduced using site-directed spin labeling and Monte Carlo sampling. Nucleic Acids Res 2013; 42:2789-97. [PMID: 24293651 PMCID: PMC3936745 DOI: 10.1093/nar/gkt1219] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The tumor suppressor protein p53 regulates numerous signaling pathways by specifically recognizing diverse p53 response elements (REs). Understanding the mechanisms of p53-DNA interaction requires structural information on p53 REs. However, such information is limited as a 3D structure of any RE in the unbound form is not available yet. Here, site-directed spin labeling was used to probe the solution structures of REs involved in p53 regulation of the p21 and Bax genes. Multiple nanometer distances in the p21-RE and BAX-RE, measured using a nucleotide-independent nitroxide probe and double-electron-electron-resonance spectroscopy, were used to derive molecular models of unbound REs from pools of all-atom structures generated by Monte-Carlo simulations, thus enabling analyses to reveal sequence-dependent DNA shape features of unbound REs in solution. The data revealed distinct RE conformational changes on binding to the p53 core domain, and support the hypothesis that sequence-dependent properties encoded in REs are exploited by p53 to achieve the energetically most favorable mode of deformation, consequently enhancing binding specificity. This work reveals mechanisms of p53-DNA recognition, and establishes a new experimental/computational approach for studying DNA shape in solution that has far-reaching implications for studying protein-DNA interactions.
Collapse
Affiliation(s)
- Xiaojun Zhang
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Stoop M, Meher G, Karri P, Krishnamurthy R. Chemical etiology of nucleic acid structure: the pentulofuranosyl oligonucleotide systems: the (1'→3')-β-L-ribulo, (4'→3')-α-L-xylulo, and (1'→3')-α-L-xylulo nucleic acids. Chemistry 2013; 19:15336-45. [PMID: 24150882 DOI: 10.1002/chem.201302219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Indexed: 11/11/2022]
Abstract
Under potentially prebiotic scenarios, ribose (pentose), the component of RNA is formed in meager amounts, as opposed to ribulose and xylulose (pentuloses). Consequently, replacement of ribose in RNA, with pentulose sugars, gives rise to prospective oligonucleotide candidates that are potentially prebiotic structural variants of RNA that could be formed by the same type of chemical pathways that gave rise to RNA from ribose. The potentially natural alternative (1'→3')-ribulo oligonucleotides and (4'→3')- and (1'→3')-xylulo oligonucleotides consisting of adenine and thymine were synthesized and found to exhibit no self-pairing or cross-pairing with RNA. This signifies that even though pentulose sugars may have been abundant in a prebiotic scenario, the pentulose nucleic acids (NAs), if and when formed, would not have been competitors of RNA, or interfered with the emergence of RNA as a functional informational system. The reason for the lack of base pairing in pentulose NA highlights the contrasting and central role played by the furanosyl ring in RNA and pentulose NA, enabling and optimizing the base pairing in RNA, while impeding it in pentulose NA.
Collapse
Affiliation(s)
- Matthias Stoop
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037 (USA), Fax: (+1) 858-784-8-9573
| | | | | | | |
Collapse
|
11
|
Moriguchi T, Sekine M, Shinozuka K. Novel method of the synthesis and hybridization properties of an oligonucleotide containing non-ionic diisopropylsilyl internucleotide linkage. Bioorg Med Chem 2013; 21:8013-8. [PMID: 24183587 DOI: 10.1016/j.bmc.2013.08.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 10/26/2022]
Abstract
Efficient synthesis of a dithymidine dinucleotide analog bearing a diisopropylsilyl linkage instead of a phosphodiester linkage is described with respect to its incorporation into oligonucleotides. The diisopropylsilyl linkage was introduced into the oligonucleotide by preparation of the phosphoramidite derivative of a dithymidine dimer unit. The diisopropylsilyl-modified oligonucleotide exhibited hybridization behavior with both single strand and duplex DNA. The thermal stability of both the duplex and triplex showed a relative instability compared to the corresponding natural phosphodiester DNA, because of the steric hindrance of the isopropyl group on the silicon atom.
Collapse
Affiliation(s)
- Tomohisa Moriguchi
- Division of Molecular Science, Faculty of Science and Technology, Gunma University, Tenjincho 1-5-1, Kiryu, Gunma, Japan.
| | | | | |
Collapse
|
12
|
Moelling K. What contemporary viruses tell us about evolution: a personal view. Arch Virol 2013; 158:1833-48. [PMID: 23568292 PMCID: PMC3755228 DOI: 10.1007/s00705-013-1679-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 02/14/2013] [Indexed: 12/11/2022]
Abstract
Recent advances in information about viruses have revealed novel and surprising properties such as viral sequences in the genomes of various organisms, unexpected amounts of viruses and phages in the biosphere, and the existence of giant viruses mimicking bacteria. Viruses helped in building genomes and are driving evolution. Viruses and bacteria belong to the human body and our environment as a well-balanced ecosystem. Only in unbalanced situations do viruses cause infectious diseases or cancer. In this article, I speculate about the role of viruses during evolution based on knowledge of contemporary viruses. Are viruses our oldest ancestors?
Collapse
Affiliation(s)
- Karin Moelling
- Max Planck Institute for Molecular Genetics, Ihnestr 63-73, 14195, Berlin, Germany.
| |
Collapse
|
13
|
Sheng J, Gan J, Huang Z. Structure-based DNA-targeting strategies with small molecule ligands for drug discovery. Med Res Rev 2013; 33:1119-73. [PMID: 23633219 DOI: 10.1002/med.21278] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nucleic acids are the molecular targets of many clinical anticancer drugs. However, compared with proteins, nucleic acids have traditionally attracted much less attention as drug targets in structure-based drug design, partially because limited structural information of nucleic acids complexed with potential drugs is available. Over the past several years, enormous progresses in nucleic acid crystallization, heavy-atom derivatization, phasing, and structural biology have been made. Many complicated nucleic acid structures have been determined, providing new insights into the molecular functions and interactions of nucleic acids, especially DNAs complexed with small molecule ligands. Thus, opportunities have been created to further discover nucleic acid-targeting drugs for disease treatments. This review focuses on the structure studies of DNAs complexed with small molecule ligands for discovering lead compounds, drug candidates, and/or therapeutics.
Collapse
Affiliation(s)
- Jia Sheng
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303, USA
| | | | | |
Collapse
|
14
|
McManus FP, Khaira A, Noronha AM, Wilds CJ. Preparation of covalently linked complexes between DNA and O(6)-alkylguanine-DNA alkyltransferase using interstrand cross-linked DNA. Bioconjug Chem 2013; 24:224-33. [PMID: 23347328 DOI: 10.1021/bc300553u] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
O(6)-alkylguanine-DNA alkyltransferases (AGT) are responsible for the removal of alkylation at both the O(6) atom of guanine and O(4) atom of thymine. AGT homologues show vast substrate differences with respect to the size of the adduct and which alkylated atoms they can restore. The human AGT (hAGT) has poor capabilities for removal of methylation at the O(4) atom of thymidine, which is not the case in most homologues. No structural data are available to explain this poor hAGT repair. We prepared and characterized O(6)G-butylene-O(4)T (XLGT4) and O(6)G-heptylene-O(4)T (XLGT7) interstrand cross-linked (ICL) DNA as probes for hAGT and the Escherichia coli homologues, OGT and Ada-C, for the formation of DNA-AGT covalent complexes. XLGT7 reacted only with hAGT and did so with a cross-linking efficiency of 25%, while XLGT4 was inert to all AGT tested. The hAGT mediated repair of XLGT7 occurred slowly, on the order of hours as opposed to the repair of O(6)-methyl-2'-deoxyguanosine which requires seconds. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the repair reaction revealed the formation of a covalent complex with an observed migration in accordance with a DNA-AGT complex. The identity of this covalent complex, as determined by mass spectrometry, was composed of a heptamethylene bridge between the O(4) atom of thymidine (in an 11-mer DNA strand) to residue Cys145 of hAGT. This procedure can be applied to produce well-defined covalent complexes between AGT with DNA.
Collapse
Affiliation(s)
- Francis P McManus
- Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke St. West, Montréal, QC, Canada H4B 1R6
| | | | | | | |
Collapse
|
15
|
|
16
|
Popova AM, Hatmal MM, Frushicheva M, Price EA, Qin PZ, Haworth IS. Nitroxide sensing of a DNA microenvironment: mechanistic insights from EPR spectroscopy and molecular dynamics simulations. J Phys Chem B 2012; 116:6387-96. [PMID: 22574834 PMCID: PMC3382087 DOI: 10.1021/jp303303v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The behavior of the nitroxide spin labels 1-oxyl-4-bromo-2,2,5,5-tetramethylpyrroline (R5a) and 1-oxyl-2,2,5,5-tetramethylpyrroline (R5) attached at a phosphorothioate-substituted site in a DNA duplex is modulated by the DNA in a site- and stereospecific manner. A better understanding of the mechanisms of R5a/R5 sensing of the DNA microenvironment will enhance our capability to relate information from nitroxide spectra to sequence-dependent properties of DNA. Toward this goal, electron paramagnetic resonance (EPR) spectroscopy and molecular dynamics (MD) simulations were used to investigate R5 and R5a attached as R(p) and S(p) diastereomers at phosphorothioate (pS)C(7) of d(CTACTG(pS)C(7)Y(8)TTAG). d(CTAAAGCAGTAG) (Y = T or U). X-band continuous-wave EPR spectra revealed that the dT(8) to dU(8) change alters nanosecond rotational motions of R(p)-R5a but produces no detectable differences for S(p)-R5a, R(p)-R5, and S(p)-R5. MD simulations were able to qualitatively account for these spectral variations and provide a plausible physical basis for the R5/R5a behavior. The simulations also revealed a correlation between DNA backbone B(I)/B(II) conformations and R5/R5a rotational diffusion, thus suggesting a direct connection between DNA local backbone dynamics and EPR-detectable R5/R5a motion. These results advance our understanding of how a DNA microenvironment influences nitroxide motion and the observed EPR spectra. This may enable use of R5/R5a for a quantitative description of the sequence-dependent properties of large biologically relevant DNA molecules.
Collapse
Affiliation(s)
- Anna M. Popova
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0744
| | - Ma’mon M. Hatmal
- Department of Biochemistry, University of Southern California, Los Angeles, California 90033-1039
| | - Maria Frushicheva
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0744
| | - Eric A. Price
- Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-0744
| | - Peter Z. Qin
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0744
| | - Ian S. Haworth
- Department of Biochemistry, University of Southern California, Los Angeles, California 90033-1039
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, California 90089-9121
| |
Collapse
|
17
|
Wu J, Fu Y, He Z, Han Y, Zheng L, Zhang J, Li W. Growth mechanisms of fluorescent silver clusters regulated by polymorphic DNA templates: a DFT study. J Phys Chem B 2012; 116:1655-65. [PMID: 22242908 DOI: 10.1021/jp206251v] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The aggregation behaviors of silver atoms modulated by polymorphic DNA templates involving i-motif, G-quadruplex, and the Watson-Crick duplex, were investigated by using the density functional theory (DFT) calculations, combining with the experimental characterizations of CD, UV, fluorescence measurements and TEM, in order to understand the reason in the molecular level that polymorphic DNA templates affect the fluorescence emitting species of Ag nanomaterials. First, the affinity sites of silver ions on different DNA templates were analyzed by using DFT calculations, and the conformational variations of DNA templates caused by silver ions and atoms were disclosed. Second, the aggregation behaviors of silver atoms constrained by the polymorphic DNA templates were studied by DFT modeling, and distinct fluorescence property of nanosilvers templated by polymorphic DNA were evaluated using the time-dependent DFT calculations. It is illustrated that with the DNA template adopting i-motif or the duplex the silver atoms tend to aggregate inside the encapsulated spaces of nucleobases, and the formed silver nanoclusters are positively charged with high fluorescent spectral features; whereas with the template of the G-quadruplex the silver atoms are preferential to aggregate outside of the G-tetrad, which results in the formation of larger silver crystals without fluorescence property. The results obtained here are useful to explore the nucleation and growth mechanism of silver nanomaterials regulated by the structure-specific DNA templates, which is important to rational design of desirable fluorescent emitters for sensing in the field from biology to nanoscience.
Collapse
Affiliation(s)
- Jiangjiexing Wu
- Key Laboratory for Green Chemical Technology MOE, Tianjin University, Tianjin 300072, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
18
|
Abstract
Metal ions play a key role in nucleic acid structure and activity. Elucidation of the rules that govern the binding of metal ions is therefore an essential step for better understanding of the nucleic acid functions. This review is as an update to a preceding one (Metal Ions Biol. Syst., 1996, 32, 91-134), in which we offered a general view of metal ion interactions with mono-, di-, tri-, and oligonucleotides in the solid state, based on their crystal structures reported before 1994. In this chapter, we survey all the crystal structures of metal ion complexes with nucleotides involving oligonucleotides reported after 1994 and we have tried to uncover new characteristic metal bonding patterns for mononucleotides and oligonucleotides with A-RNA and A/B/Z-DNA fragments that form duplexes. We do not cover quadruplexes, duplexes with metal-mediated base-pairs, tRNAs, rRNAs in ribosome, ribozymes, and nucleic acid-drug and -protein complexes. Factors that affect metal binding to mononucleotides and oligonucleotide duplexes are also dealt with.
Collapse
|
19
|
Sissi C, Gatto B, Palumbo M. The evolving world of protein-G-quadruplex recognition: a medicinal chemist's perspective. Biochimie 2011; 93:1219-30. [PMID: 21549174 PMCID: PMC7126356 DOI: 10.1016/j.biochi.2011.04.018] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Accepted: 04/20/2011] [Indexed: 01/02/2023]
Abstract
The physiological and pharmacological role of nucleic acids structures folded into the non canonical G-quadruplex conformation have recently emerged. Their activities are targeted at vital cellular processes including telomere maintenance, regulation of transcription and processing of the pre-messenger or telomeric RNA. In addition, severe conditions like cancer, fragile X syndrome, Bloom syndrome, Werner syndrome and Fanconi anemia J are related to genomic defects that involve G-quadruplex forming sequences. In this connection G-quadruplex recognition and processing by nucleic acid directed proteins and enzymes represents a key event to activate or deactivate physiological or pathological pathways. In this review we examine protein-G-quadruplex recognition in physiologically significant conditions and discuss how to possibly exploit the interactions' selectivity for targeted therapeutic intervention.
Collapse
Affiliation(s)
- Claudia Sissi
- Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, Padua, Italy
| | | | | |
Collapse
|
20
|
Skov J, Bryld T, Lindegaard D, Nielsen KE, Højland T, Wengel J, Petersen M. Synthesis and structural characterization of piperazino-modified DNA that favours hybridization towards DNA over RNA. Nucleic Acids Res 2010; 39:1953-65. [PMID: 21062815 PMCID: PMC3061067 DOI: 10.1093/nar/gkq1123] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report the synthesis of two C4'-modified DNA analogues and characterize their structural impact on dsDNA duplexes. The 4'-C-piperazinomethyl modification stabilizes dsDNA by up to 5°C per incorporation. Extension of the modification with a butanoyl-linked pyrene increases the dsDNA stabilization to a maximum of 9°C per incorporation. Using fluorescence, ultraviolet and nuclear magnetic resonance (NMR) spectroscopy, we show that the stabilization is achieved by pyrene intercalation in the dsDNA duplex. The pyrene moiety is not restricted to one intercalation site but rather switches between multiple sites in intermediate exchange on the NMR timescale, resulting in broad lines in NMR spectra. We identified two intercalation sites with NOE data showing that the pyrene prefers to intercalate one base pair away from the modified nucleotide with its linker curled up in the minor groove. Both modifications are tolerated in DNA:RNA hybrids but leave their melting temperatures virtually unaffected. Fluorescence data indicate that the pyrene moiety is residing outside the helix. The available data suggest that the DNA discrimination is due to (i) the positive charge of the piperazino ring having a greater impact in the narrow and deep minor groove of a B-type dsDNA duplex than in the wide and shallow minor groove of an A-type DNA:RNA hybrid and (ii) the B-type dsDNA duplex allowing the pyrene to intercalate and bury its apolar surface.
Collapse
Affiliation(s)
- Joan Skov
- Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | | | | | | | | | | | | |
Collapse
|
21
|
Rosu F, Gabelica V, Joly L, Grégoire G, De Pauw E. Zwitterionic i-motif structures are preserved in DNA negatively charged ions produced by electrospray mass spectrometry. Phys Chem Chem Phys 2010; 12:13448-54. [DOI: 10.1039/c0cp00782j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|