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Chen E, Trajkovski M, Lee H, Nyovanie S, Martin K, Dean W, Tahiliani M, Plavec J, Yatsunyk L. Structure of native four-repeat satellite III sequence with non-canonical base interactions. Nucleic Acids Res 2024; 52:3390-3405. [PMID: 38381082 PMCID: PMC11014236 DOI: 10.1093/nar/gkae113] [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] [Received: 07/05/2023] [Revised: 01/31/2024] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
Tandem-repetitive DNA (where two or more DNA bases are repeated numerous times) can adopt non-canonical secondary structures. Many of these structures are implicated in important biological processes. Human Satellite III (HSat3) is enriched for tandem repeats of the sequence ATGGA and is located in pericentromeric heterochromatin in many human chromosomes. Here, we investigate the secondary structure of the four-repeat HSat3 sequence 5'-ATGGA ATGGA ATGGA ATGGA-3' using X-ray crystallography, NMR, and biophysical methods. Circular dichroism spectroscopy, thermal stability, native PAGE, and analytical ultracentrifugation indicate that this sequence folds into a monomolecular hairpin with non-canonical base pairing and B-DNA characteristics at concentrations below 0.9 mM. NMR studies at 0.05-0.5 mM indicate that the hairpin is likely folded-over into a compact structure with high dynamics. Crystallographic studies at 2.5 mM reveal an antiparallel self-complementary duplex with the same base pairing as in the hairpin, extended into an infinite polymer. The non-canonical base pairing includes a G-G intercalation sandwiched by sheared A-G base pairs, leading to a cross-strand four guanine stack, so called guanine zipper. The guanine zippers are spaced throughout the structure by A-T/T-A base pairs. Our findings lend further insight into recurring structural motifs associated with the HSat3 and their potential biological functions.
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Affiliation(s)
- Erin Chen
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Marko Trajkovski
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Hyun Kyung Lee
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Samantha Nyovanie
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Kailey N Martin
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - William L Dean
- Structural Biology Program JG Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Mamta Tahiliani
- Department of Biology, New York University, New York, NY 10003, USA
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Liliya A Yatsunyk
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
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2
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de Oliveira Martins E, Weber G. Nearest-neighbour parametrization of DNA single, double and triple mismatches at low sodium concentration. Biophys Chem 2024; 306:107156. [PMID: 38157701 DOI: 10.1016/j.bpc.2023.107156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/27/2023] [Accepted: 12/17/2023] [Indexed: 01/03/2024]
Abstract
DNA mismatches, that is, base pairs different from the canonical AT and CG, are involved in numerous biological processes and can be a problem for technological applications such as PCR amplification. The nearest-neighbour (NN) model is the standard approach for predicting melting temperatures and is used in methods of secondary structure predictions and modelling of hybridization kinetics. However, despite its biological and technological importance, existing NN parameters that include DNA mismatches are incomplete, and those available were obtained from a limited set of melting temperature at high sodium concentration. To our knowledge, there is currently no NN set of parameters for up to three mismatches covering all configurations at low sodium concentrations. Here, we are applying the NN model to a large set of 4096 published melting temperatures, covering all combinations of single, double and triple mismatches. Dealing with such a large set of temperature is challenging in several ways, bringing new methodological problems. Here, optimizing a large number of 252 independent parameters has required the development of a new method where we readjust the seed parameters using the definition of the Gibbs free energy. The new parameters predict the training set within 1.1 °C and the validation set to 2.7 °C.
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Affiliation(s)
- Erik de Oliveira Martins
- Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil; Escola Politécnica, Centro Universitário Católica do Leste de Minas Gerais, 35170-056 Coronel Fabriciano, MG, Brazil
| | - Gerald Weber
- Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
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3
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Troisi R, Napolitano V, Rossitto E, Osman W, Nagano M, Wakui K, Popowicz G, Yoshimoto K, Sica F. Steric hindrance and structural flexibility shape the functional properties of a guanine-rich oligonucleotide. Nucleic Acids Res 2023; 51:8880-8890. [PMID: 37503836 PMCID: PMC10484730 DOI: 10.1093/nar/gkad634] [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] [Received: 12/15/2022] [Revised: 06/27/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023] Open
Abstract
Ligand/protein molecular recognition involves a dynamic process, whereby both partners require a degree of structural plasticity to regulate the binding/unbinding event. Here, we present the characterization of the interaction between a highly dynamic G-rich oligonucleotide, M08s-1, and its target protein, human α-thrombin. M08s-1 is the most active anticoagulant aptamer selected thus far. Circular dichroism and gel electrophoresis analyses indicate that both intramolecular and intermolecular G-quadruplex structures are populated in solution. The presence of thrombin stabilises the antiparallel intramolecular chair-like G-quadruplex conformation, that provides by far the main contribution to the biological activity of the aptamer. The crystal structure of the thrombin-oligonucleotide complex reveals that M08s-1 adopts a kinked structural organization formed by a G-quadruplex domain and a long duplex module, linked by a stretch of five purine bases. The quadruplex motif hooks the exosite I region of thrombin and the duplex region is folded towards the surface of the protein. This structural feature, which has never been observed in other anti-exosite I aptamers with a shorter duplex motif, hinders the approach of a protein substrate to the active site region and may well explain the significant increase in the anticoagulant activity of M08s-1 compared to the other anti-exosite I aptamers.
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Affiliation(s)
- Romualdo Troisi
- Department of Chemical Sciences, University of Naples Federico II, Naples 80126, Italy
| | - Valeria Napolitano
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Emanuele Rossitto
- Department of Chemical Sciences, University of Naples Federico II, Naples 80126, Italy
| | - Waleed Osman
- Research and Development Division, LinkBIO Co., Ltd., The ICI Center, 5270 Terada, Toride-shi, Ibaraki 302-0021, Japan
| | - Masanobu Nagano
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Koji Wakui
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Grzegorz M Popowicz
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Keitaro Yoshimoto
- Research and Development Division, LinkBIO Co., Ltd., The ICI Center, 5270 Terada, Toride-shi, Ibaraki 302-0021, Japan
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Filomena Sica
- Department of Chemical Sciences, University of Naples Federico II, Naples 80126, Italy
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4
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Satange R, Kao SH, Chien CM, Chou SH, Lin CC, Neidle S, Hou MH. Staggered intercalation of DNA duplexes with base-pair modulation by two distinct drug molecules induces asymmetric backbone twisting and structure polymorphism. Nucleic Acids Res 2022; 50:8867-8881. [PMID: 35871296 PMCID: PMC9410880 DOI: 10.1093/nar/gkac629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/24/2022] [Accepted: 07/22/2022] [Indexed: 12/12/2022] Open
Abstract
The use of multiple drugs simultaneously targeting DNA is a promising strategy in cancer therapy for potentially overcoming single drug resistance. In support of this concept, we report that a combination of actinomycin D (ActD) and echinomycin (Echi), can interact in novel ways with native and mismatched DNA sequences, distinct from the structural effects produced by either drug alone. Changes in the former with GpC and CpG steps separated by a A:G or G:A mismatch or in a native DNA with canonical G:C and C:G base pairs, result in significant asymmetric backbone twists through staggered intercalation and base pair modulations. A wobble or Watson–Crick base pair at the two drug-binding interfaces can result in a single-stranded ‘chair-shaped’ DNA duplex with a straight helical axis. However, a novel sugar-edged hydrogen bonding geometry in the G:A mismatch leads to a ‘curved-shaped’ duplex. Two non-canonical G:C Hoogsteen base pairings produce a sharply kinked duplex in different forms and a four-way junction-like superstructure, respectively. Therefore, single base pair modulations on the two drug-binding interfaces could significantly affect global DNA structure. These structures thus provide a rationale for atypical DNA recognition via multiple DNA intercalators and a structural basis for the drugs’ potential synergetic use.
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Affiliation(s)
- Roshan Satange
- Institute of Genomics and Bioinformatics, National Chung Hsing University , Taichung 402, Taiwan
- Ph.D. Program in Medical Biotechnology, National Chung Hsing University , Taichung 402, Taiwan
| | - Shih-Hao Kao
- Institute of Biotechnology, National Chung Hsing University , Taichung 402, Taiwan
| | - Ching-Ming Chien
- Institute of Genomics and Bioinformatics, National Chung Hsing University , Taichung 402, Taiwan
| | - Shan-Ho Chou
- Institute of Biochemistry, National Chung Hsing University , Taichung 402, Taiwan
| | - Chi-Chien Lin
- Institute of Biomedical Science, National Chung Hsing University , Taichung 402, Taiwan
| | - Stephen Neidle
- The School of Pharmacy, University College London , London WC1N 1AX, United Kingdom
| | - Ming-Hon Hou
- Institute of Genomics and Bioinformatics, National Chung Hsing University , Taichung 402, Taiwan
- Ph.D. Program in Medical Biotechnology, National Chung Hsing University , Taichung 402, Taiwan
- Institute of Biotechnology, National Chung Hsing University , Taichung 402, Taiwan
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5
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Aoki K, Salam MA, Hu NH, Murayama K. Crystal structure of [Rh2(μ-OAc)2(μ-HNOCCF3)2(theophylline)2]·6H2O. Metal bonding to theophylline at the unexpected N(9) site due to the crystal packing effect and a review on intra-molecular interligand interactions affecting metal bonding properties of theophylline. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Oliveira LM, Long AS, Brown T, Fox KR, Weber G. Melting temperature measurement and mesoscopic evaluation of single, double and triple DNA mismatches. Chem Sci 2020; 11:8273-8287. [PMID: 34094181 PMCID: PMC8163305 DOI: 10.1039/d0sc01700k] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Unlike the canonical base pairs AT and GC, the molecular properties of mismatches such as hydrogen bonding and stacking interactions are strongly dependent on the identity of the neighbouring base pairs. As a result, due to the sheer number of possible combinations of mismatches and flanking base pairs, only a fraction of these have been studied in varying experiments or theoretical models. Here, we report on the melting temperature measurement and mesoscopic analysis of contiguous DNA mismatches in nearest-neighbours and next-nearest neighbour contexts. A total of 4032 different mismatch combinations, including single, double and triple mismatches were covered. These were compared with 64 sequences containing all combinations of canonical base pairs in the same location under the same conditions. For a substantial number of single mismatch configurations, 15%, the measured melting temperatures were higher than the least stable AT base pair. The mesoscopic calculation, using the Peyrard-Bishop model, was performed on the set of 4096 sequences, and resulted in estimates of on-site and nearest-neighbour interactions that can be correlated to hydrogen bonding and base stacking. Our results confirm many of the known properties of mismatches, including the peculiar sheared stacking of tandem GA mismatches. More intriguingly, it also reveals that a number of mismatches present strong hydrogen bonding when flanked on both sites by other mismatches. To highlight the applicability of our results, we discuss a number of practical situations such as enzyme binding affinities, thymine DNA glycosylase repair activity, and trinucleotide repeat expansions.
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Affiliation(s)
- Luciana M Oliveira
- Departamento de Física, Universidade Federal de Minas Gerais 31270-901 Belo Horizonte MG Brazil +55 31 3409 5600 +55 31 3409 6616
| | - Adam S Long
- School of Biological Sciences, University of Southampton Life Sciences Building 85 Southampton SO17 1BJ UK
| | - Tom Brown
- Department of Chemistry, University of Oxford Oxford UK
| | - Keith R Fox
- School of Biological Sciences, University of Southampton Life Sciences Building 85 Southampton SO17 1BJ UK
| | - Gerald Weber
- Departamento de Física, Universidade Federal de Minas Gerais 31270-901 Belo Horizonte MG Brazil +55 31 3409 5600 +55 31 3409 6616
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7
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Bonsaii M, Gholivand K, Abdi K, Valmoozi AAE, Khosravi M. A combined experimental and computational study on the interaction of nitrogen mustards with DNA. MEDCHEMCOMM 2016. [DOI: 10.1039/c6md00264a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the present work, we suggest that the role of water in the reaction of nitrogen mustards with DNA is more than what was thought before. Nitrogen mustards become activated when they are hydrated by water.
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Affiliation(s)
- Mahyar Bonsaii
- Department of Chemistry
- Islamic Azad University
- Tehran
- Iran
| | | | - Khosrou Abdi
- Department of Medicinal Chemistry and Radiopharmacy
- Tehran University of Medical Sciences
- Tehran
- Iran
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8
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Wang Q, Yang C, Xiang Y, Yuan R, Chai Y. Dual amplified and ultrasensitive electrochemical detection of mutant DNA Biomarkers based on nuclease-assisted target recycling and rolling circle amplifications. Biosens Bioelectron 2014; 55:266-71. [DOI: 10.1016/j.bios.2013.12.034] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/20/2013] [Accepted: 12/11/2013] [Indexed: 11/26/2022]
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9
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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.
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10
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Furukawa K, Hattori M, Ohki T, Kitamura Y, Kitade Y, Ueno Y. Nucleic acid probe containing fluorescent tricyclic base-linked acyclonucleoside for detection of single nucleotide polymorphisms. Bioorg Med Chem 2011; 20:16-24. [PMID: 22177406 DOI: 10.1016/j.bmc.2011.11.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 11/19/2011] [Accepted: 11/21/2011] [Indexed: 11/16/2022]
Abstract
The development of a reliable and simple method for detecting single nucleotide polymorphisms (SNPs), common genetic variations in the human genome, is currently an important research area because SNPs are important for identifying disease-causing genes and for pharmacogenetic studies. Here, we developed a novel method for SNP detection. We designed and synthesized DNA probes containing a fluorescent tricyclic base-linked acyclonucleoside P. The type of nucleobases involved in the SNP sites in the DNA and RNA targets could be determined using four DNA probes containing P. Thus, this system would provide a novel and simple method for detecting SNPs in DNA and RNA targets.
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Affiliation(s)
- Kinji Furukawa
- Department of Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
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11
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Reinstein O, Neves MAD, Saad M, Boodram SN, Lombardo S, Beckham SA, Brouwer J, Audette GF, Groves P, Wilce MCJ, Johnson PE. Engineering a structure switching mechanism into a steroid-binding aptamer and hydrodynamic analysis of the ligand binding mechanism. Biochemistry 2011; 50:9368-76. [PMID: 21942676 DOI: 10.1021/bi201361v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The steroid binding mechanism of a DNA aptamer was studied using isothermal titration calorimetry (ITC), NMR spectroscopy, quasi-elastic light scattering (QELS), and small-angle X-ray spectroscopy (SAXS). Binding affinity determination of a series of steroid-binding aptamers derived from a parent cocaine-binding aptamer demonstrates that substituting a GA base pair with a GC base pair governs the switch in binding specificity from cocaine to the steroid deoxycholic acid (DCA). Binding of DCA to all aptamers is an enthalpically driven process with an unfavorable binding entropy. We engineered into the steroid-binding aptamer a ligand-induced folding mechanism by shortening the terminal stem by two base pairs. NMR methods were used to demonstrate that there is a transition from a state where base pairs are formed in one stem of the free aptamer, to where three stems are formed in the DCA-bound aptamer. The ability to generate a ligand-induced folding mechanism into a DNA aptamer architecture based on the three-way junction of the cocaine-binding aptamer opens the door to obtaining a series of aptamers all with ligand-induced folding mechanisms but triggered by different ligands. Hydrodynamic data from diffusion NMR spectroscopy, QELS, and SAXS show that for the aptamer with the full-length terminal stem there is a small amount of structure compaction with DCA binding. For ligand binding by the short terminal stem aptamer, we propose a binding mechanism where secondary structure forms upon DCA binding starting from a free structure where the aptamer exists in a compact form.
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Affiliation(s)
- Oren Reinstein
- Department of Chemistry, York University, Toronto, Ontario, Canada M3J 1P3
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12
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Chang CYJ, Stellwagen NC. Tandem GA residues on opposite sides of the loop in molecular beacon-like DNA hairpins compact the loop and increase hairpin stability. Biochemistry 2011; 50:9148-57. [PMID: 21942650 DOI: 10.1021/bi201263n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The free solution electrophoretic mobilities and thermal stabilities of hairpins formed by two complementary 26-nucleotide oligomers have been measured by capillary electrophoresis. The oligomers are predicted to form molecular beacon-like hairpins with 5 bp stems and 16 nucleotides in the loop. One hairpin, called hairpin2 (hp2), migrates with a relatively fast free solution mobility and exhibits melting temperatures that are reasonably well predicted by the popular structure-prediction program Mfold. Its complement, called hairpin1 (hp1), migrates with a slower free solution mobility and forms a stable hairpin only in solutions containing ≥200 mM Na(+). The melting temperatures observed for hp1 are ~18 °C lower than those observed for hp2 and ~20 °C lower than those predicted by Mfold. The greater thermal stability of hp2 is due to the presence of tandem GA residues on opposite sides of the loop. If the corresponding TC residues in the hp1 loop are replaced by tandem GA residues, the melting temperatures of the modified hairpin are close to those observed for hp2. Eliminating the tandem GA residues in the hp2 loop significantly decreases the thermal stability of hp2. If the loops are replaced by a loop of 16 thymine residues, the free solution mobilities and thermal stabilities of the T-loop hairpin are equal to those observed for hp1. Hence, the loop of hp1 appears to be relatively unstructured, with few base-base stacking interactions. Interactions between tandem GA residues on opposite sides of the hp2 loop appear to compact the loop and increase hairpin stability.
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Affiliation(s)
- Chun Yaw Joel Chang
- Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, United States
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13
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Neves MA, Reinstein O, Saad M, Johnson PE. Defining the secondary structural requirements of a cocaine-binding aptamer by a thermodynamic and mutation study. Biophys Chem 2010; 153:9-16. [DOI: 10.1016/j.bpc.2010.09.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/09/2010] [Accepted: 09/09/2010] [Indexed: 10/19/2022]
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14
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Neves MAD, Reinstein O, Johnson PE. Defining a stem length-dependent binding mechanism for the cocaine-binding aptamer. A combined NMR and calorimetry study. Biochemistry 2010; 49:8478-87. [PMID: 20735071 DOI: 10.1021/bi100952k] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have used a combined approach of NMR spectroscopy and isothermal titration calorimetry (ITC) to determine the ligand-binding mechanism employed by a cocaine-binding aptamer. We found that the length of the stem containing the 3' and 5' termini determines the nature of the binding mechanism. When this stem is six base pairs long, the secondary structure of the aptamer is fully folded in the free form and only putative tertiary interactions form with ligand binding. If this stem is shortened by three base pairs, the free form of the aptamer contains little secondary structure, and ligand binding triggers secondary structure formation and folding. This binding mechanism is supported by both NMR spectral changes and the ITC measured heat capacity of binding (ΔC(p)°). For the aptamer with the long stem the ΔC(p)° value is -557 ± 29 cal mol(-1) K(-1) and for the aptamer with the short stem the ΔC(p)° value is -922 ± 51 cal mol(-1) K(-1). Chemical shift perturbation data and the observation of intermolecular NOEs indicate that the three-way junction is the site of ligand binding.
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Affiliation(s)
- Miguel A D Neves
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
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15
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Abstract
One obstacle to achieving complete understanding of the principles underlying sequence-dependent recognition of DNA is the paucity of structural data for DNA recognition sequences in their free (unbound) state. Here, we carried out crystallization screening of 50 DNA duplexes containing cognate protein binding sites and obtained new crystal structures of free DNA binding sites for three distinct modes of DNA recognition: anti-parallel beta strands (MetR), helix-turn-helix motif + hinge helices (PurR), and zinc fingers (Zif268). Structural changes between free and protein-bound DNA are manifested differently in each case. The new DNA structures reveal that distinctive sequence-dependent DNA geometry dominates recognition by MetR, protein-induced bending of DNA dictates recognition by PurR, and deformability of DNA along the A-B continuum is important in recognition by Zif268. Together, our findings show that crystal structures of free DNA binding sites provide new information about the nature of protein-DNA interactions and thus lend insights towards a structural code for DNA recognition.
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16
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Lu Y, Li X, Zhang L, Yu P, Su L, Mao L. Aptamer-based electrochemical sensors with aptamer-complementary DNA oligonucleotides as probe. Anal Chem 2008; 80:1883-90. [PMID: 18290636 DOI: 10.1021/ac7018014] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study describes a facile and general strategy for the development of aptamer-based electrochemical sensors with a high specificity toward the targets and a ready regeneration feature. Very different from the existing strategies for the development of electrochemical aptasensors with the aptamers as the probes, the strategy proposed here is essentially based on the utilization of the aptamer-complementary DNA (cDNA) oligonucleotides as the probes for electrochemical sensing. In this context, the sequences at both ends of the cDNA are tailor-made to be complementary and both the redox moiety (i.e., ferrocene in this study) and thiol group are labeled onto the cDNA. The labeled cDNA are hybridized with their respective aptamers (i.e., ATP- and thrombin-binding aptamers in this study) to form double-stranded DNA (ds-DNA) and the electrochemical aptasensors are prepared by self-assembling the labeled ds-DNA onto Au electrodes. Upon target binding, the aptamers confined onto electrode surface dissociate from their respective cDNA oligonucleotides into the solution and the single-stranded cDNA could thus tend to form a hairpin structure through the hybridization of the complementary sequences at both its ends. Such a conformational change of the cDNA resulting from the target binding-induced dissociation of the aptamers essentially leads to the change in the voltammetric signal of the redox moiety labeled onto the cDNA and thus constitutes the mechanism for the electrochemical aptasensors for specific target sensing. The aptasensors demonstrated here with the cDNA as the probe are readily regenerated and show good responses toward the targets. This study may offer a new and relatively general approach to electrochemical aptasensors with good analytical properties and potential applications.
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Affiliation(s)
- Ying Lu
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, the Chinese Academy of Sciences, Beijing 100080, China
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17
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Min JH, Pavletich NP. Recognition of DNA damage by the Rad4 nucleotide excision repair protein. Nature 2007; 449:570-5. [PMID: 17882165 DOI: 10.1038/nature06155] [Citation(s) in RCA: 305] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 08/07/2007] [Indexed: 01/03/2023]
Abstract
Mutations in the nucleotide excision repair (NER) pathway can cause the xeroderma pigmentosum skin cancer predisposition syndrome. NER lesions are limited to one DNA strand, but otherwise they are chemically and structurally diverse, being caused by a wide variety of genotoxic chemicals and ultraviolet radiation. The xeroderma pigmentosum C (XPC) protein has a central role in initiating global-genome NER by recognizing the lesion and recruiting downstream factors. Here we present the crystal structure of the yeast XPC orthologue Rad4 bound to DNA containing a cyclobutane pyrimidine dimer (CPD) lesion. The structure shows that Rad4 inserts a beta-hairpin through the DNA duplex, causing the two damaged base pairs to flip out of the double helix. The expelled nucleotides of the undamaged strand are recognized by Rad4, whereas the two CPD-linked nucleotides become disordered. These findings indicate that the lesions recognized by Rad4/XPC thermodynamically destabilize the Watson-Crick double helix in a manner that facilitates the flipping-out of two base pairs.
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Affiliation(s)
- Jung-Hyun Min
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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Carmieli R, Larsen TM, Reed GH, Zein S, Neese F, Goldfarb D. The catalytic Mn2+ sites in the enolase-inhibitor complex: crystallography, single-crystal EPR, and DFT calculations. J Am Chem Soc 2007; 129:4240-52. [PMID: 17367133 PMCID: PMC2538446 DOI: 10.1021/ja066124e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Crystals of Zn2+/Mn2+ yeast enolase with the inhibitor PhAH (phosphonoacetohydroxamate) were grown under conditions with a slight preference for binding of Zn2+ at the higher affinity site, site I. The structure of the Zn2+/Mn2+-PhAH complex was solved at a resolution of 1.54 A, and the two catalytic metal binding sites, I and II, show only subtle displacement compared to that of the corresponding complex with the native Mg2+ ions. Low-temperature echo-detected high-field (W-band, 95 GHz) EPR (electron paramagnetic resonance) and 1H ENDOR (electron-nuclear double resonance) were carried out on a single crystal, and rotation patterns were acquired in two perpendicular planes. Analysis of the rotation patterns resolved a total of six Mn2+ sites, four symmetry-related sites of one type and two out of the four of the other type. The observation of two chemically inequivalent Mn2+ sites shows that Mn2+ ions populate both sites I and II and the zero-field splitting (ZFS) tensors of the Mn2+ in the two sites were determined. The Mn2+ site with the larger D value was assigned to site I based on the 1H ENDOR spectra, which identified the relevant water ligands. This assignment is consistent with the seemingly larger deviation of site I from octahedral symmetry, compared to that of site II. The ENDOR results gave the coordinates of the protons of two water ligands, and adding them to the crystal structure revealed their involvement in a network of H bonds stabilizing the binding of the metal ions and PhAH. Although specific hyperfine interactions with the inhibitor were not determined, the spectroscopic properties of the Mn2+ in the two sites were consistent with the crystal structure. Density functional theory (DFT) calculations carried out on a cluster representing the catalytic site, with Mn2+ in site I and Zn2+ in site II, and vice versa, gave overestimated D values on the order of the experimental ones, although the larger D value was found for Mn2+ in site II rather than in site I. This discrepancy was attributed to the high sensitivity of the ZFS parameters to the Mn-O bond lengths and orientations, such that small, but significant, differences between the optimized and crystal structures alter the ZFS considerably, well above the difference between the two sites.
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Affiliation(s)
- Raanan Carmieli
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot, Israel
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19
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Bala R, Sharma RP, Sharma R, Salas JM, Quirós M, Harrison WT. Cationic cobaltammines as anion receptors: Synthesis, characterization and X-ray structure of bis-(hexaamminecobalt(III)) tris-(hydrogenarsenate) tetrahydrate. J Mol Struct 2007. [DOI: 10.1016/j.molstruc.2006.05.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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20
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Liang X, Kuhn H, Frank-Kamenetskii MD. Monitoring single-stranded DNA secondary structure formation by determining the topological state of DNA catenanes. Biophys J 2006; 90:2877-89. [PMID: 16461397 PMCID: PMC1414558 DOI: 10.1529/biophysj.105.074104] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-stranded DNA (ssDNA) has essential biological functions during DNA replication, recombination, repair, and transcription. The structure of ssDNA must be better understood to elucidate its functions. However, the available data are too limited to give a clear picture of ssDNA due to the extremely capricious structural features of ssDNA. In this study, by forming DNA catenanes and determining their topology (the linking number, Lk) through the electrophoretic analysis, we demonstrate that the studies of catenanes formed from two ssDNA molecules can yield valuable new information about the ssDNA secondary structure. We construct catenanes out of two short (60/70 nt) ssDNA molecules by enzymatic cyclization of linear oligodeoxynucleotides. The secondary structure formed between the two DNA circles determines the topology (the Lk value) of the constructed DNA catenane. Thus, formation of the secondary structure is experimentally monitored by observing the changes of linking number with sequences and conditions. We found that the secondary structure of ssDNA is much easier to form than expected: the two strands in an internal loop in the folded ssDNA structure prefer to braid around each other rather than stay separately forming a loop, and a duplex containing only mismatched basepairs can form under physiological conditions.
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Affiliation(s)
- Xingguo Liang
- Center for Advanced Biotechnology and Department of Biomedical Engineering, Boston University, Massachusetts 02215, USA
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21
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Control of Chloride Ion Exchange by DNA Hybridization at Polypyrrole Electrode. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1871-0069(05)01009-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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22
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Sundaralingam M, Ponnuswamy PK. Stability of DNA Duplexes with Watson−Crick Base Pairs: A Predicted Model. Biochemistry 2004; 43:16467-76. [PMID: 15610041 DOI: 10.1021/bi048158+] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conformational stability (difference between the free energies of the folded and unfolded states, DeltaG degrees ) of a DNA duplex is considered as a function of component energy terms, hydrophobic, base stacking, hydrogen bonding, van der Waals, and electrostatic, and a trinucleotide-level helix stiffness parameter measured in terms of its Young's modulus. Hydrophobic and base stacking energy components were determined with the use of the crystal structure data of 30 DNA duplexes judicially selected within a resolution of 1.5 A, and hydrogen bonding, van der Waals and electrostatic terms were determined through an extensive review of experimental and theoretical studies. The stiffness indices for the trinucleotides were the ones realized by M. M. Gromiha [(2000) J. Biol. Phys. 26, 43-50] using the crystal structure data of 70 DNA duplexes. The unfolded state was treated in the classical way to determine its stability. Thermodynamically determined DeltaG degrees values for 111 DNA duplexes, with the number of base pairs ranging from 4 to 16, were selected in two sets, and the regression equation formed with one set was used to predict the stabilities of the other set, taking the energy components and the stiffness parameter to be independent variables. The computed energy terms indicate that the base stacking and hydrogen bonding forces are the dominant and the hydrophobic and electrostatic forces the weak partners in imparting stability to the duplexes. This model predicts DeltaG degrees values for DNA duplexes examined with a level of accuracy similar to that used for predictions made by the widely used nearest-neighbor models. The uniqueness of this model is that it combines the crystal and thermodynamic data for interpretation of conformational stability.
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Affiliation(s)
- M Sundaralingam
- Macromolecular Center, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
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23
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Korolev N, Lyubartsev AP, Laaksonen A, Nordenskiöld L. Molecular dynamics simulation study of oriented polyamine- and Na-DNA: sequence specific interactions and effects on DNA structure. Biopolymers 2004; 73:542-55. [PMID: 15048778 DOI: 10.1002/bip.10583] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Molecular dynamics (MD) computer simulations have been carried out on four systems that correspond to an infinite array of parallel ordered B-DNA, mimicking the state in oriented DNA fibers and also being relevant for crystals of B-DNA oligonucleotides. The systems were all comprised of a periodical hexagonal cell with three identical DNA decamers, 15 water molecules per nucleotide, and counterions balancing the DNA charges. The sequence of the double helical DNA decamer was d(5'-ATGCAGTCAG)xd(5'-TGACTGCATC). The counterions were the two natural polyamines spermidine(3+) (Spd(3+)) and putrescine(2+) (Put(2+)), the synthetic polyamine diaminopropane(2+) (DAP(2+)), and the simple monovalent cation Na(+). This work compares the specific structures of the polyamine- and Na-DNA systems and how they are affected by counterion interactions. It also describes sequence-specific hydration and interaction of the cations with DNA. The local DNA structure is dependent on the nature of the counterion. Even the very similar polyamines, Put(2+) and DAP(2+), show clear differences in binding to DNA and in effect on hydration and local structure. Generally, the polyamines disorder the hydration of the DNA around their binding sites whereas Na(+) being bound to DNA attracts and organizes water in its vicinity. Cation binding at the selected sites in the minor and in the major groove is compared for the different polyamines and Na(+). We conclude that the synthetic polyamine (DAP(2+)) binds specifically to several structural and sequence-specific motifs on B-DNA, unlike the natural polyamines, Spd(3+) and Put(2+). This specificity of DAP(2+) compared to the more dynamic behavior of Spd(3+) and Put(2+) may explain why the latter polyamines are naturally occurring in cells.
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Affiliation(s)
- Nikolay Korolev
- School of Biological Sciences, NTU - Nanyang Technological University, No. 1 Nanyang Walk, Blk. 5, Level 3, Singapore 637616
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24
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Hou MH, Robinson H, Gao YG, Wang AHJ. Crystal structure of the [Mg2+-(chromomycin A3)2]-d(TTGGCCAA)2 complex reveals GGCC binding specificity of the drug dimer chelated by a metal ion. Nucleic Acids Res 2004; 32:2214-22. [PMID: 15107489 PMCID: PMC407830 DOI: 10.1093/nar/gkh549] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Revised: 03/29/2004] [Accepted: 03/29/2004] [Indexed: 11/15/2022] Open
Abstract
The anticancer antibiotic chromomycin A3 (Chro) is a DNA minor groove binding drug belonging to the aureolic family. Chro likely exerts its activity by interfering with replication and transcription. Chro forms a dimer, mediated by a divalent metal ion, which binds to G/C-rich DNA. Herein we report the first crystal structure of Chro bound to d(TTG GCCAA)2 DNA duplex solved by multiwavelength anomalous diffraction (MAD) based on the chelated Co3+ ion. The structure of the Mg2+ complex was subsequently refined at 2.15 A resolution, which revealed two complexes of metal-coordinated dimers of Chro bound to the octamer DNA duplex in the asymmetric unit. The metal ion is octahedrally coordinated to the O1 and O9 oxygen atoms of the chromophore (CPH), and two water molecules act as the fifth and sixth ligands. The two coordinated water molecules are hydrogen bonded to O2 atoms of C5 and C13 bases. The Chro dimer binds at and significantly widens the minor groove of the GGCC sequence. The long axis of each chromophore lies along and stacks over the sugar-phosphate backbone with the two attached saccharide moieties (rings A/B and C/D/E) wrapping across the minor groove. DNA is kinked by 30 degrees and 36 degrees in the two complexes, respectively. Six G-specific hydrogen bonds between Chro and DNA provide the GGCC sequence specificity. Interestingly, DNA in concert with Chro appears to act as an effective template to catalyze the deamination of Co(NH3)6(3+), as shown by circular dichroism and crystal structure data. Our results present useful structural information for designing new anticancer drug derivatives in the future.
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Affiliation(s)
- Ming-Hon Hou
- Institute of Biological Chemistry, Academia Sinica, Taipei, 115 Taiwan
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25
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Subirana JA, Soler-Lopez M. Cations as hydrogen bond donors: a view of electrostatic interactions in DNA. ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 2003; 32:27-45. [PMID: 12598364 DOI: 10.1146/annurev.biophys.32.110601.141726] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cations are bound to nucleic acids in a solvated state. High-resolution X-ray diffraction studies of oligonucleotides provide a detailed view of Mg2+, and occasionally other ions bound to DNA. In a survey of several such structures, certain general observations emerge. First, cations bind preferentially to the guanine base in the major groove or to phosphate group oxygen atoms. Second, cations interact with DNA most frequently via water molecules in their primary solvation shell, direct ion-DNA contacts being only rarely observed. Thus, the solvated ions should be viewed as hydrogen bond donors in addition to point charges. Finally, ion interaction sites are readily exchangeable: The same site may be occupied by any ion, including spermine, as well as by a water molecule.
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Affiliation(s)
- Juan A Subirana
- Departament d'Enginyeria Quimica, Universitat Politecnica de Catalunya, Barcelona, Spain.
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26
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Abstract
Single-stranded DNA or double-stranded DNA has the potential to adopt a wide variety of unusual duplex and hairpin motifs in the presence (trans) or absence (cis) of ligands. Several principles for the formation of those unusual structures have been established through the observation of a number of recurring structural motifs associated with different sequences. These include: (i) internal loops of consecutive mismatches can occur in a B-DNA duplex when sheared base pairs are adjacent to each other to confer extensive cross- and intra-strand base stacking; (ii) interdigitated (zipper-like) duplex structures form instead when sheared G*A base pairs are separated by one or two pairs of purine*purine mismatches; (iii) stacking is not restricted to base, deoxyribose also exhibits the potential to do so; (iv) canonical G*C or A.T base pairs are flexible enough to exhibit considerable changes from the regular H-bonded conformation. The paired bases become stacked when bracketed by sheared G.A base pairs, or become extruded out and perpendicular to their neighboring bases in the presence of interacting drugs; (v) the purine-rich and pyrimidine-rich loop structures are notably different in nature. The purine-rich loops form compact triloop structures closed by a sheared G*A, A*A, A*C or sheared-like G(anti)*C(syn) base pair that is stacked by a single residue. On the other hand, the pyrimidine-rich loops with a thymidine in the first position exhibit no base pairing but are characterized by the folding of the thymidine residue into the minor groove to form a compact loop structure. Identification of such diverse duplex or hairpin motifs greatly enlarges the repertoire for unusual DNA structural formation.
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Affiliation(s)
- Shan-Ho Chou
- Department of Life Science, National Central University, Jung-Li, 320, Taiwan, ROC
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27
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Heidenfelder BL, Makhov AM, Topal MD. Hairpin formation in Friedreich's ataxia triplet repeat expansion. J Biol Chem 2003; 278:2425-31. [PMID: 12441336 DOI: 10.1074/jbc.m210643200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Triplet repeat tracts occur throughout the human genome. Expansions of a (GAA)(n)/(TTC)(n) repeat tract during its transmission from parent to child are tightly associated with the occurrence of Friedreich's ataxia. Evidence supports DNA slippage during DNA replication as the cause of the expansions. DNA slippage results in single-stranded expansion intermediates. Evidence has accumulated that predicts that hairpin structures protect from DNA repair the expansion intermediates of all of the disease-associated repeats except for those of Friedreich's ataxia. How the latter repeat expansions avoid repair remains a mystery because (GAA)(n) and (TTC)(n) repeats are reported not to self-anneal. To characterize the Friedreich's ataxia intermediates, we generated massive expansions of (GAA)(n) and (TTC)(n) during DNA replication in vitro using human polymerase beta and the Klenow fragment of Escherichia coli polymerase I. Electron microscopy, endonuclease cleavage, and DNA sequencing of the expansion products demonstrate, for the first time, the occurrence of large and growing (GAA)(n) and (TTC)(n) hairpins during DNA synthesis. The results provide unifying evidence that predicts that hairpin formation during DNA synthesis mediates all of the disease-associated, triplet repeat expansions.
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Affiliation(s)
- Brooke L Heidenfelder
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, 27599-7295, USA
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28
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Hou MH, Robinson H, Gao YG, Wang AHJ. Crystal structure of actinomycin D bound to the CTG triplet repeat sequences linked to neurological diseases. Nucleic Acids Res 2002; 30:4910-7. [PMID: 12433994 PMCID: PMC137167 DOI: 10.1093/nar/gkf619] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2002] [Revised: 09/20/2002] [Accepted: 09/20/2002] [Indexed: 12/31/2022] Open
Abstract
The potent anticancer drug actinomycin D (ActD) acts by binding to DNA GpC sequences, thereby interfering with essential biological processes including replication, transcription and topoisomerase. Certain neurological diseases are correlated with expansion of (CTG)n trinucleotide sequences, which contain many contiguous GpC sites separated by a single base pair. In order to characterize the binding of ActD to CTG triplet repeat sequences, we carried out heat denaturation and CD analyses, which showed that adjacent GpC sequences flanking a T:T mismatch are preferred ActD-binding sites, and that ActD binding results in a conformational transition to A-type structure. The structural basis of the strong binding of ActD to neighboring GpC sites flanking a T:T mismatch was provided by the crystal structure of ActD bound to ATGCTGCAT, which contains a CTG triplet sequence. Binding of two ActD molecules to GCTGC causes a kink in the DNA helix. In addition, using a synthetic self-priming DNA model, 5'-(CAG)4(CTG)(16)-3', we observed that ActD can trap the cruciform or duplexes of (CTG)n and interfere with the expansion process of CTG triplet repeats as shown by gel electrophoretic expansion assay. Our results may provide the possible biological consequence of ActD bound to CTG triplet repeat sequences.
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Affiliation(s)
- Ming-Hon Hou
- Institute of Biological Chemistry, Academia Sinica, Taipei, 115 Taiwan
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29
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Poyner RR, Larsen TM, Wong SW, Reed GH. Functional and structural changes due to a serine to alanine mutation in the active-site flap of enolase. Arch Biochem Biophys 2002; 401:155-63. [PMID: 12054465 DOI: 10.1016/s0003-9861(02)00024-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Crystallographic and kinetic methods have been used to characterize a site-specific variant of yeast enolase in which Ser 39 in the active-site flap has been changed to Ala. In the wild-type enzyme, the carbonyl and hydroxyl groups of Ser 39 chelate the second equivalent of divalent metal ion, effectively anchoring the flap over the fully liganded active site. With Mg(2+) as the activating cation, S39A enolase has <0.01% of wild-type activity as reported previously [J.M. Brewer, C.V. Glover, M.J. Holland, L. Lebioda, Biochim. Biophys. Acta 1383 (2) (1998) 351-355]. Measurements of (2)H kinetic isotope effects indicate that the proton abstraction from 2-phosphoglycerate (2-PGA) is significantly rate determining. Analysis of the isotope effects provides information on the relative rates of formation and breakdown of the enolate intermediate. Moreover, assays with different species of divalent metal ions reveal that with S39A enolase (unlike the case of wild-type enolase), more electrophilic metal ions promote higher activities. The kinetic results with the S39A variant support the notions that a rate-limiting product release lowers the activity of wild-type enolase with more electrophilic metal ions and that the metal ions are used to acidify the C2-proton of 2-PGA. The S39A enolase was co-crystallized with Mg(2+) and the inhibitor phosphonoacetohydroxamate (PhAH). The structure was solved and refined at a resolution of 2.1 A. The structure confirms the conjecture that the active-site flap is opened in the mutant protein. PhAH chelates to both Mg ions as in the corresponding structure of the wild-type complex. Positions of the side chains of catalytic groups, Lys 345 and Glu 211, and of "auxiliary" residues Glu 168 and Lys 396 are virtually unchanged relative to the complex with the wild-type protein. His 159, which hydrogen bonds to the phosphonate oxygens in the wild-type complex, is 5.7 A from the closest phosphonate oxygen, and the loop (154-166) containing His 159 is shifted away from the active center. A peripheral loop, Glu 251-Gly 275, also moves to open access to the active site.
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Affiliation(s)
- Russell R Poyner
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53705, USA
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30
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Affiliation(s)
- Anton S. Petrov
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
| | - Gene Lamm
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
| | - George R. Pack
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
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31
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Hou MH, Lin SB, Yuann JM, Lin WC, Wang AH, Kan Ls L. Effects of polyamines on the thermal stability and formation kinetics of DNA duplexes with abnormal structure. Nucleic Acids Res 2001; 29:5121-8. [PMID: 11812845 PMCID: PMC97540 DOI: 10.1093/nar/29.24.5121] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The effects of ions (i.e. Na+, Mg2+ and polyamines including spermidine and spermine) on the stability of various DNA oligonucleotides in solution were studied. These synthetic DNA molecules contained sequences that mimic various cellular DNA structures, such as duplexes, bulged loops, hairpins and/or mismatched base pairs. Melting temperature curves obtained from the ultraviolet spectroscopic experiments indicated that the effectiveness of the stabilization of cations on the duplex formation follows the order of spermine > spermidine > Mg2+ > Na+ > Tris-HCl buffer alone at pH 7.3. Circular dichroism spectra showed that salts and polyamines did not change the secondary structures of those DNA molecules under study. Surface plasmon resonance (SPR) observations suggested that the rates of duplex formation are independent of the kind of cations used or the structure of the duplexes. However, the rate constants of DNA duplex dissociation decrease in the same order when those cations are involved. The enhancement of the duplex stability by polyamines, especially spermine, can compensate for the instability caused by abnormal structures (e.g. bulged loops, hairpins or mismatches). The effects can be so great as to make the abnormal DNAs as stable as the perfect duplex, both kinetically and thermodynamically. Our results may suggest that the interconversion of various DNA structures can be accomplished readily in the presence of polyamine. This may be relevant in understanding the role of DNA polymorphism in cells.
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Affiliation(s)
- M H Hou
- Institute of Chemistry, Academia Sinica, Taipei, 115 Taiwan
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32
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Abstract
A series of DNA heptadecamers containing the DNA analogues of RNA E-like 5'-d(GXA)/(AYG)-5' motifs (X/Y is complementary T/A, A/T, C/G, or G/C pair) were studied using nuclear magnetic resonance (NMR) methodology and distance geometry (DG)/molecular dynamics (MD) approaches. Such oligomers reveal excellent resolution in NMR spectra and exhibit many unusual nuclear Overhauser effects (NOEs) that allow for good characterization of an unusual zipper-like conformation with zipper-like Watson-Crick base-pairs; the potential canonical X.Y H-bonding is not present, and the central X/Y pairs are transformed instead into inter-strand stacks that are bracketed by sheared G.A base-pairs. Such phenomenal structural change is brought about mainly through two backbone torsional angle adjustments, i.e. delta from C2'-endo to C3'-endo for the sugar puckers of unpaired residues and gamma from gauche(+) to trans for the following 3'-adenosine residues. Such motifs are analogous to the previously studied (GGA)(2) motif presumably present in the human centromeric (TGGAA)(n) tandem repeat sequence. The novel zipper-like motifs are only 4-7 deg. C less stable than the (GGA)(2) motif, suggesting that inter-strand base stacking plays an important role in stabilizing unusual nucleic acid structures. The discovery that canonical Watson-Crick G.C or A.T hydrogen-bonded pairs can be transformed into stacking pairs greatly increases the repertoire for unusual nucleic acid structural motifs.
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Affiliation(s)
- S H Chou
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan.
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Korolev S, Dementieva I, Sanishvili R, Minor W, Otwinowski Z, Joachimiak A. Using surface-bound rubidium ions for protein phasing. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2001; 57:1008-12. [PMID: 11418770 PMCID: PMC3691023 DOI: 10.1107/s0907444901007302] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2001] [Accepted: 05/02/2001] [Indexed: 11/10/2022]
Abstract
Rubidium is a monovalent metal that can be used as a counterion in protein solutions. X-ray anomalous scattering from rubidium ions bound to the protein surface was used for phasing of the crystal structure of the hsp60 apical domain from Thermus thermophilus. Multiple-wavelength anomalous dispersion (MAD) data were collected from a crystal obtained from a solution containing 0.2 M rubidium salt. One molecule of protein (147 amino acids) binds one well ordered and one poorly ordered Rb atom. Phases calculated with the program SHARP were sufficient for automatic tracing and side-chain assignment using the program ARP/wARP. The data show that bound rubidium ions can be used to determine protein structures and to study the interaction of monovalent metal ions with proteins and other macromolecules.
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Affiliation(s)
- S. Korolev
- Biosciences Division and Structural Biology Center, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
| | - I. Dementieva
- Biosciences Division and Structural Biology Center, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
| | - R. Sanishvili
- Biosciences Division and Structural Biology Center, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
| | - W. Minor
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA
| | - Z. Otwinowski
- Department of Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, TX 75235, USA
| | - A. Joachimiak
- Biosciences Division and Structural Biology Center, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
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Robinson H, Gao YG, Yang X, Sanishvili R, Joachimiak A, Wang AH. Crystallographic analysis of a novel complex of actinomycin D bound to the DNA decamer CGATCGATCG. Biochemistry 2001; 40:5587-92. [PMID: 11341823 DOI: 10.1021/bi002859z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The potent anticancer drug actinomycin D (ActD) acts by binding to DNA, thereby interfering with replication and transcription. ActD inhibits RNA polymerase far more specifically than DNA polymerase. Such discrimination is not easily understood by the conventional DNA binding mode of ActD. We have solved and refined at 1.7 A resolution the crystal structure of ActD complexed to CGATCGATCG, which contains no canonical GpC binding sequence. The crystal data are space group P4(3)2(1)2, a = b = 47.01 A, and c = 160.37 A. The structure was solved by the multiple wavelength anomalous diffraction method using a 5-bromo-U DNA. The asymmetric unit of the unit cell contains two independent dimers of a novel slipped duplex complex consisting of two decamer DNA strands bound with two ActD drug molecules. (The DNA in one dimer is numbered C1 to G10 in one strand and C11 to G20 in the complementary strand and in the second dimer, C101 to G110 and C111 to G120, respectively.) The structure reveals a highly unusual ActD binding mode in which the DNA adopts a slipped duplex with the A3-T4/A13-T14 dinucleotides looped out. ActD intercalates between G2-C11* (C11* being from a symmetry-related molecule) and C5-G20 base pairs. Two such slipped duplex-ActD complexes bound to each other by mutually intercalating their T4/T14 bases into the helix cavities (located between C5-G20 and G6-C19 base pairs) of neighboring complexes, forming a dimer of drug-DNA complexes. The binding site mimics the drug binding at the elongation point during transcription. Modeling studies show that the ActD-DNA complex fits snugly in the active site cavity in RNA polymerase but not in DNA polymerase. This may explain the strong preference of ActD inhibition toward transcription.
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Affiliation(s)
- H Robinson
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Organization, Replication, Transposition, and Repair of DNA. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50030-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yang XL, Robinson H, Gao YG, Wang AHJ. Binding of a Macrocyclic Bisacridine and Ametantrone to CGTACG Involves Similar Unusual Intercalation Platforms. Biochemistry 2000. [DOI: 10.1021/bi001319z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiang-lei Yang
- Department of Biochemistry, School of Molecular & Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Howard Robinson
- Department of Biochemistry, School of Molecular & Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Yi-Gui Gao
- Department of Biochemistry, School of Molecular & Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Andrew H.-J. Wang
- Department of Biochemistry, School of Molecular & Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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Jovine L, Djordjevic S, Rhodes D. The crystal structure of yeast phenylalanine tRNA at 2.0 A resolution: cleavage by Mg(2+) in 15-year old crystals. J Mol Biol 2000; 301:401-14. [PMID: 10926517 DOI: 10.1006/jmbi.2000.3950] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have re-determined the crystal structure of yeast tRNA(Phe) to 2. 0 A resolution using 15 year old crystals. The accuracy of the new structure, due both to higher resolution data and formerly unavailable refinement methods, consolidates the previous structural information, but also reveals novel details. In particular, the water structure around the tightly bound Mg(2+) is now clearly resolved, and hence provides more accurate information on the geometry of the magnesium-binding sites and the role of water molecules in coordinating the metal ions to the tRNA. We have assigned a total of ten magnesium ions and identified a partly conserved geometry for high-affinity Mg(2+ )binding. In the electron density map there is also clear density for a spermine molecule binding in the major groove of the TPsiC arm and also contacting a symmetry-related tRNA molecule. Interestingly, we have also found that two specific regions of the tRNA in the crystals are partially cleaved. The sites of hydrolysis are within the D and anticodon loops in the vicinity of Mg(2+).
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Affiliation(s)
- L Jovine
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 2QH, UK
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