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[PMID]: 28973477 [Au] Autor: Einarson OJ; Sen D [Ad] Endereço: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada. [Ti] Título: Self-biotinylation of DNA G-quadruplexes via intrinsic peroxidase activity. [So] Source: Nucleic Acids Res;45(17):9813-9822, 2017 Sep 29. [Is] ISSN: 1362-4962 [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: The striking and ubiquitous in vitro affinity between hemin and DNA/RNA G-quadruplexes raises the intriguing possibility of its relevance to biology. To date, no satisfactory experimental framework has been reported for investigating such a possibility. Complexation by G-quadruplexes leads to activation of the bound hemin toward catalysis of 1- and 2-electron oxidative reactions, with phenolic compounds being particularly outstanding substrates. We report here a strategy for exploiting that intrinsic peroxidase activity of hemin•G-quadruplex complexes for self-biotinylation of their G-quadruplex component. Such self-biotinylation occurs with good efficiency and high discrimination in vitro, being specific for G-quadruplexes and not for duplexes. The biotinylated DNA, moreover, remains amenable to polymerase chain reaction amplification, rendering it suitable for analysis by ChIP-Seq and related methods. We anticipate that this self-biotinylation methodology will also serve as a sensitive tool, orthogonal to existing ones, for identifying, labeling and pulling down cellular RNA and DNA G-quadruplexes in general, as well as proteins bound to or proximal to such quadruplexes. [Mh] Termos MeSH primário: DNA Catalítico/química Quadruplex G Hemina/química Oligonucleotídeos/química Peroxidases/química [Mh] Termos MeSH secundário: Biocatálise Técnicas Biossensoriais/métodos Biotina/química Biotinilação Peróxido de Hidrogênio/química Cinética Mimetismo Molecular Oxirredução Fenóis/química Reação em Cadeia da Polimerase Estreptavidina/química Tiramina/química [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (DNA, Catalytic); 0 (Oligonucleotides); 0 (Phenols); 0 (biotin tyramine); 6SO6U10H04 (Biotin); 743LRP9S7N (Hemin); 9013-20-1 (Streptavidin); BBX060AN9V (Hydrogen Peroxide); EC 1.11.1.- (Peroxidases); X8ZC7V0OX3 (Tyramine) [Em] Mês de entrada: 1710 [Cu] Atualização por classe: 171017 [Lr] Data última revisão: 171017 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 171004 [St] Status: MEDLINE [do] DOI: 10.1093/nar/gkx765

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[PMID]: 28731305 [Au] Autor: Palou-Mir J; Barceló-Oliver M; Sigel RKO [Ti] Título: The Role of Lead(II) in Nucleic Acids. [So] Source: Met Ions Life Sci;17, 2017 04 10. [Is] ISSN: 1559-0836 [Cp] País de publicação: Netherlands [La] Idioma: eng [Ab] Resumo: Although lead(II) is naturally not associated with nucleic acids, this metal ions has been applied with DNA and RNA in various contexts. Pb2+ is an excellent hydrolytic metal ion for nucleic acids, which is why it is mainly used as probing agent for secondary structure and to determine metal ion binding sites both in vitro and in vivo. A further application of lead(II) is in structural studies, i.e., NMR, but also in X-ray crystallography, mostly using this heavy metal to solve the phase problem in the latter method. The structures of tRNAPhe, RNase P, HIV-1 DIS, and the leadzyme are discussed here in detail. A major part of this review is devoted to the cleavage properties of lead(II) with RNA because of its excellence in catalyzing phosphodiester cleavage. Metal ion binding sites in large naturally occurring ribozymes are regularly determined by Pb2+ cleavage, and also in the in vitro selected socalled leadzyme, this metal ion is the decisive key to backbone cleavage at a specific site. Lead(II) was used in the first in vitro selection that yielded a catalytic DNA, i.e., the DNAzyme named GR5. Next to the GR5, the so-called 8-17E is the second most prominent DNAzyme today. Derivatives of these two lead(II)-dependent DNAzymes, as well as the G-quadruplex forming PS2.M have been applied to detect lead(II) in the lower nanomolar range not only in the test tube but also in body fluids. Due to the toxicity of lead(II) for living beings, this is a highly active research field. Finally, further applications of lead(II)-dependent DNAzymes, e.g., in the construction of nanocomputers, are also discussed. [Mh] Termos MeSH primário: Chumbo/química Ácidos Nucleicos/química [Mh] Termos MeSH secundário: DNA Catalítico/química DNA Catalítico/metabolismo Conformação de Ácido Nucleico [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; REVIEW [Nm] Nome de substância: 0 (DNA, Catalytic); 0 (Nucleic Acids); 2P299V784P (Lead) [Em] Mês de entrada: 1709 [Cu] Atualização por classe: 170914 [Lr] Data última revisão: 170914 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170722 [St] Status: MEDLINE

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[PMID]: 28658518 [Au] Autor: Zhou W; Saran R; Ding J; Liu J [Ad] Endereço: Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada. [Ti] Título: Two Completely Different Mechanisms for Highly Specific Na Recognition by DNAzymes. [So] Source: Chembiochem;18(18):1828-1835, 2017 Sep 19. [Is] ISSN: 1439-7633 [Cp] País de publicação: Germany [La] Idioma: eng [Ab] Resumo: Our view of the interaction between Na and nucleic acids was changed by a few recently discovered Na -specific RNA-cleaving DNAzymes. In addition to nonspecific electrostatic interactions, highly specific recognition is also possible. Herein, two such DNAzymes, named EtNa and Ce13d, are compared to elucidate their mechanisms of Na binding. Mutation studies indicate that they have different sequence requirements. Phosphorothioate (PS) substitution at the scissile phosphate drops the activity of EtNa 140-fold, and it cannot be rescued by thiophilic Cd or Mn , whereas the activity of PS-modified Ce13d can be rescued. Na -dependent activity assays indicate that two Na ions bind cooperatively in EtNa, and each Na likely interacts with a nonbridging oxygen atom in the scissile phosphate, whereas Ce13d binds only one Na ion in a well-defined Na aptamer, and this Na ion does not directly interact with the scissile phosphate. Both DNAzymes display a normal pH-rate profile, with a single deprotonation reaction required for catalysis. For EtNa, Na fails to protect the conserved nucleotides from dimethyl sulfate attack, and no specific Na binding is detected by 2-aminopurine fluorescence, both of which are different from those observed for Ce13d. This work suggests that EtNa binds Na mainly through its scissile phosphate without significant involvement of the nucleotides in the enzyme strand, whereas Ce13d has a well-defined aptamer for Na binding. Therefore, DNA has at least two distinct ways to achieve highly selective Na binding. [Mh] Termos MeSH primário: DNA Catalítico/metabolismo Sódio/metabolismo [Mh] Termos MeSH secundário: 2-Aminopurina/química Sequência de Bases Biocatálise DNA Catalítico/genética Íons/química Conformação de Ácido Nucleico Oligonucleotídeos/metabolismo Fosfatos/química Sódio/química Espectrometria de Fluorescência [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (DNA, Catalytic); 0 (Ions); 0 (Oligonucleotides); 0 (Phosphates); 452-06-2 (2-Aminopurine); 9NEZ333N27 (Sodium); TYM4M7EWCW (thiophosphoric acid) [Em] Mês de entrada: 1709 [Cu] Atualização por classe: 170928 [Lr] Data última revisão: 170928 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170629 [St] Status: MEDLINE [do] DOI: 10.1002/cbic.201700184

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[PMID]: 28654322 [Au] Autor: Fresco JR; Amosova O [Ad] Endereço: Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; email: jrfresco@princeton.edu , amosova@princeton.edu. [Ti] Título: Site-Specific Self-Catalyzed DNA Depurination: A Biological Mechanism That Leads to Mutations and Creates Sequence Diversity. [So] Source: Annu Rev Biochem;86:461-484, 2017 Jun 20. [Is] ISSN: 1545-4509 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Self-catalyzed DNA depurination is a sequence-specific physiological mechanism mediated by spontaneous extrusion of a stem-loop catalytic intermediate. Hydrolysis of the 5'G residue of the 5'GA/TGG loop and of the first 5'A residue of the 5'GAGA loop, together with particular first stem base pairs, specifies their hydrolysis without involving protein, cofactor, or cation. As such, this mechanism is the only known DNA catalytic activity exploited by nature. The consensus sequences for self-depurination of such G- and A-loop residues occur in all genomes examined across the phyla, averaging one site every 2,000-4,000 base pairs. Because apurinic sites are subject to error-prone repair, leading to substitution and short frameshift mutations, they are both a source of genome damage and a means for creating sequence diversity. Their marked overrepresentation in genomes, and largely unchanging density from the lowest to the highest organisms, indicate their selection over the course of evolution. The mutagenicity at such sites in many human genes is associated with loss of function of key proteins responsible for diverse diseases. [Mh] Termos MeSH primário: Adenina/metabolismo Síndrome de Bloom/genética DNA Catalítico/genética Guanina/metabolismo Polimorfismo Genético Síndrome de Werner/genética [Mh] Termos MeSH secundário: Evolução Biológica Síndrome de Bloom/metabolismo Síndrome de Bloom/patologia Catálise Reparo do DNA DNA Catalítico/metabolismo DNA Cruciforme/genética DNA Cruciforme/metabolismo DNA de Cadeia Simples/genética DNA de Cadeia Simples/metabolismo Seres Humanos Hidrólise Sequências Repetidas Invertidas Mutação Síndrome de Werner/metabolismo Síndrome de Werner/patologia Globinas beta/genética Globinas beta/metabolismo [Pt] Tipo de publicação: JOURNAL ARTICLE; REVIEW [Nm] Nome de substância: 0 (DNA, Catalytic); 0 (DNA, Cruciform); 0 (DNA, Single-Stranded); 0 (beta-Globins); 5Z93L87A1R (Guanine); JAC85A2161 (Adenine) [Em] Mês de entrada: 1707 [Cu] Atualização por classe: 170704 [Lr] Data última revisão: 170704 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170628 [St] Status: MEDLINE [do] DOI: 10.1146/annurev-biochem-070611-095951

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[PMID]: 28533132 [Au] Autor: Cheng M; Zhou J; Jia G; Ai X; Mergny JL; Li C [Ad] Endereço: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China. Electronic address: mpcheng@dicp.ac.cn. [Ti] Título: Relations between the loop transposition of DNA G-quadruplex and the catalytic function of DNAzyme. [So] Source: Biochim Biophys Acta;1861(8):1913-1920, 2017 08. [Is] ISSN: 0006-3002 [Cp] País de publicação: Netherlands [La] Idioma: eng [Ab] Resumo: The structures of DNA G-quadruplexes are essential for their functions in vivo and in vitro. Our present study revealed that sequential order of the three G-quadruplex loops, that is, loop transposition, could be a critical factor to determinate the G-quadruplex conformation and consequently improved the catalytic function of G-quadruplex based DNAzyme. In the presence of 100mM K , loop transposition induced one of the G-quadruplex isomers which shared identical loops but differed in the sequential order of loops into a hybrid topology while the others into predominately parallel topologies. D NMR spectroscopy and mutation analysis suggested that the hydrogen bonding from loops residues with nucleotides in flanking sequences may be responsible for the stabilization of the different conformations. A well-known DNAzyme consisting of G-quadruplex and hemin (Ferriprotoporphyrin IX chloride) was chosen to test the catalytic function. We found that the loop transposition could enhance the reaction rate obviously by increasing the hemin binding affinity to G-quadruplex. These findings disclose the relations between the loop transposition, G-quadruplex conformation and catalytic function of DNAzyme. [Mh] Termos MeSH primário: Biocatálise DNA Catalítico/fisiologia Quadruplex G [Mh] Termos MeSH secundário: Hemina/metabolismo Ligações de Hidrogênio [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (DNA, Catalytic); 743LRP9S7N (Hemin) [Em] Mês de entrada: 1710 [Cu] Atualização por classe: 171026 [Lr] Data última revisão: 171026 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170524 [St] Status: MEDLINE

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[PMID]: 28382172 [Au] Autor: Zhou W; Ding J; Liu J [Ad] Endereço: Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China, 410013.; Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1. [Ti] Título: Theranostic DNAzymes. [So] Source: Theranostics;7(4):1010-1025, 2017. [Is] ISSN: 1838-7640 [Cp] País de publicação: Australia [La] Idioma: eng [Ab] Resumo: DNAzymes are catalytically active DNA molecules that are obtained via in vitro selection. RNA-cleaving DNAzymes have attracted significant attention for both therapeutic and diagnostic applications due to their excellent programmability, stability, and activity. They can be designed to cleave a specific mRNA to down-regulate gene expression. At the same time, DNAzymes can sense a broad range of analytes. By combining these two functions, theranostic DNAzymes are obtained. This review summarizes the progress of DNAzyme for theranostic applications. First, selection of DNAzymes is briefly introduced, and some representative DNAzymes related to biological applications are summarized. Then, the applications of DNAzyme for RNA cleaving are reviewed. DNAzymes have been used to cleave RNA for treating various diseases, such as viral infection, cancer, inflammation and atherosclerosis. Several formulations have entered clinical trials. Next, the use of DNAzymes for detecting metal ions, small molecules and nucleic acids related to disease diagnosis is summarized. Finally, the theranostic applications of DNAzyme are reviewed. The challenges to be addressed include poor DNAzyme activity under biological conditions, mRNA accessibility, delivery, and quantification of gene expression. Possible solutions to overcome these challenges are discussed, and future directions of the field are speculated. [Mh] Termos MeSH primário: DNA Catalítico/metabolismo RNA/metabolismo Nanomedicina Teranóstica/métodos [Mh] Termos MeSH secundário: Animais Terapia Biológica/métodos Pesquisa Biomédica/tendências Testes Diagnósticos de Rotina/métodos Seres Humanos [Pt] Tipo de publicação: JOURNAL ARTICLE; REVIEW [Nm] Nome de substância: 0 (DNA, Catalytic); 63231-63-0 (RNA) [Em] Mês de entrada: 1710 [Cu] Atualização por classe: 171023 [Lr] Data última revisão: 171023 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170407 [St] Status: MEDLINE [do] DOI: 10.7150/thno.17736

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[PMID]: 28345892 [Au] Autor: Saran R; Kleinke K; Zhou W; Yu T; Liu J [Ad] Endereço: Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada. [Ti] Título: A Silver-Specific DNAzyme with a New Silver Aptamer and Salt-Promoted Activity. [So] Source: Biochemistry;56(14):1955-1962, 2017 Apr 11. [Is] ISSN: 1520-4995 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Most RNA-cleaving DNAzymes require a metal ion to interact with the scissile phosphate for activity. Therefore, few unmodified DNAzymes work with thiophilic metals because of their low affinity for phosphate. Recently, an Ag -specific Ag10c DNAzyme was reported via in vitro selection. Herein, Ag10c is characterized to rationalize the role of the strongly thiophilic Ag . Systematic mutation studies indicate that Ag10c is a highly conserved DNAzyme and its Ag binding is unrelated to C-Ag -C interaction. Its activity is enhanced by increasing Na concentrations in buffer. At the same metal concentration, activity decreases in the following order: Li > Na > K . Ag10c binds one Na ion and two Ag ions for catalysis. The pH-rate profile has a slope of ∼1, indicating a single deprotonation step. Phosphorothioate substitution at the scissile phosphate suggests that Na interacts with the pro-R oxygen of the phosphate, and dimethyl sulfate footprinting indicates that the DNAzyme loop is a silver aptamer binding two Ag ions. Therefore, Ag exerts its function allosterically, while the scissile phosphate interacts with Na , Li , Na , or Mg . This work suggests the possibility of isolating thiophilic metal aptamers based on DNAzyme selection, and it also demonstrates a new Ag aptamer. [Mh] Termos MeSH primário: Aptâmeros de Nucleotídeos/química DNA Catalítico/química Fosfatos/química RNA/química Prata/química [Mh] Termos MeSH secundário: Regulação Alostérica Aptâmeros de Nucleotídeos/metabolismo Pareamento de Bases Sequência de Bases Biocatálise Cátions Bivalentes Cátions Monovalentes Pegada de DNA DNA Catalítico/metabolismo Concentração de Íons de Hidrogênio Cinética Lítio/química Lítio/metabolismo Magnésio/química Magnésio/metabolismo Conformação de Ácido Nucleico Fosfatos/metabolismo Potássio/química Potássio/metabolismo RNA/metabolismo Prata/metabolismo Sódio/química Sódio/metabolismo Ésteres do Ácido Sulfúrico/química [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Aptamers, Nucleotide); 0 (Cations, Divalent); 0 (Cations, Monovalent); 0 (DNA, Catalytic); 0 (Phosphates); 0 (Sulfuric Acid Esters); 3M4G523W1G (Silver); 63231-63-0 (RNA); 9FN79X2M3F (Lithium); 9NEZ333N27 (Sodium); I38ZP9992A (Magnesium); JW5CW40Z50 (dimethyl sulfate); RWP5GA015D (Potassium) [Em] Mês de entrada: 1705 [Cu] Atualização por classe: 170515 [Lr] Data última revisão: 170515 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170328 [St] Status: MEDLINE [do] DOI: 10.1021/acs.biochem.6b01131

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[PMID]: 28323518 [Au] Autor: Dolot R; Sobczak M; Mikolajczyk B; Nawrot B [Ad] Endereço: a Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences , Department of Bioorganic Chemistry , Lódz , Poland. [Ti] Título: Synthesis, crystallization and preliminary crystallographic analysis of a 52-nucleotide DNA/2'-OMe-RNA oligomer mimicking 10-23 DNAzyme in the complex with a substrate. [So] Source: Nucleosides Nucleotides Nucleic Acids;36(4):292-301, 2017 Apr 03. [Is] ISSN: 1532-2335 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: A 52-nucleotide DNA/2'-OMe-RNA oligomer mimicking 10-23 DNAzyme in the complex with its substrate was synthesized, purified and crystallized by the hanging-drop method using 0.8 M sodium potassium tartrate as a precipitant. A data set to 1.21 Å resolution was collected from a monocrystal at 100 K using synchrotron radiation on a beamline BL14.1 at BESSY. The crystal belonged to the P2 group with unit-cell a = 49.42, b = 24.69, c = 50.23, ß = 118.48. [Mh] Termos MeSH primário: Materiais Biomiméticos/química Materiais Biomiméticos/síntese química DNA Catalítico/metabolismo Nucleotídeos/química RNA/química [Mh] Termos MeSH secundário: Sequência de Bases Técnicas de Química Sintética Cristalização RNA/genética [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (DNA, Catalytic); 0 (Nucleotides); 63231-63-0 (RNA) [Em] Mês de entrada: 1711 [Cu] Atualização por classe: 171113 [Lr] Data última revisão: 171113 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170322 [St] Status: MEDLINE [do] DOI: 10.1080/15257770.2016.1276291

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[PMID]: 28105837 [Au] Autor: Li H; Chang J; Hou T; Li F [Ad] Endereço: College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University , Qingdao 266109, People's Republic of China. [Ti] Título: HRP-Mimicking DNAzyme-Catalyzed in Situ Generation of Polyaniline To Assist Signal Amplification for Ultrasensitive Surface Plasmon Resonance Biosensing. [So] Source: Anal Chem;89(1):673-680, 2017 01 03. [Is] ISSN: 1520-6882 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: It is well-known that the horseradish peroxidase- (HRP-) mimicking DNAzyme, namely, hemin/G-quadruplex, can effectively catalyze the polymerization of aniline to form DNA-guided polyaniline. Meanwhile, polyaniline exhibits extraordinary electrical, electrochemical, and redox properties, as well as excellent SPR signal-enhancing ability. Herein, we report a novel ultrasensitive surface plasmon resonance (SPR) biosensor based on HRP-mimicking DNAzyme-catalyzed in situ formation of polyaniline for signal amplification, using bleomycin (BLM) as the proof-of-concept analyte. The recognition and the subsequent cleavage of DNA probe P1 by BLM switches off the hybridization between P1 and the G-rich DNA probe P2, resulting in less hemin/G-quadruplex complexes and reduced DNA-guided polyaniline deposition on the SPR Au disk surface. As compared to the case when BLM is absent, a significant shift in SPR angle is observed, which is dependent on the BLM concentration. Therefore, ultrasensitive SPR detection of the target BLM is realized, with a detection limit down to 0.35 pM, much lower than those reported in the literature. Moreover, the proposed SPR biosensor has been successfully applied for the detection of BLM spiked in human serum samples. The HRP-mimicking DNAzyme-catalyzed in situ polyaniline deposition and polyaniline-assisted signal amplification not only significantly improves the specificity and the sensitivity of the BLM assay but also allows the ultrasensitive detection of other biomolecules by simply changing the specific target recognition DNA sequences, thus providing a versatile SPR biosensing platform for the ultrasensitive detection of a variety of analytes and showing great potential for application in the fields of bioanalysis and clinical biomedicine. [Mh] Termos MeSH primário: Compostos de Anilina/análise Biocatálise DNA Catalítico/metabolismo Peroxidase do Rábano Silvestre/metabolismo Limite de Detecção Ressonância de Plasmônio de Superfície/métodos [Mh] Termos MeSH secundário: Compostos de Anilina/química Eletroquímica Seres Humanos [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (Aniline Compounds); 0 (DNA, Catalytic); 0 (polyaniline); EC 1.11.1.- (Horseradish Peroxidase) [Em] Mês de entrada: 1707 [Cu] Atualização por classe: 170719 [Lr] Data última revisão: 170719 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170121 [St] Status: MEDLINE [do] DOI: 10.1021/acs.analchem.6b02988

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[PMID]: 28087991 [Au] Autor: Zhou W; Saran R; Huang PJ; Ding J; Liu J [Ad] Endereço: School of Pharmaceutical Sciences, Central South University, 172 Tongzipo Road, Changsha, Hunan, 410013, China. [Ti] Título: An Exceptionally Selective DNA Cooperatively Binding Two Ca Ions. [So] Source: Chembiochem;18(6):518-522, 2017 Mar 16. [Is] ISSN: 1439-7633 [Cp] País de publicação: Germany [La] Idioma: eng [Ab] Resumo: Ca is a highly important metal ion in biology and in the environment, and thus there is extensive work in developing sensors for Ca detection. Although many Ca -binding proteins are known, few nucleic acids can selectively bind Ca . DNA-based biosensors are attractive for their high stability and excellent programmability. We report a RNA-cleaving DNAzyme, EtNa, cooperatively binding two Ca ions but to only one Mg . Four DNAzymes with known Ca -dependent activity were compared, and the EtNa had the best selectivity for Ca . The EtNa is 90 times more active in Ca than in Mg . Phosphorothioate (PS) modification showed that both non-bridging oxygen atoms at the scissile phosphate contribute equally to Ca binding. The pH-rate profile suggests two concurrent deprotonation reactions. EtNa was further engineered for Ca sensing, and found to have a detection limit of 17 µm Ca and excellent selectivity. The detection of Ca in tap water was performed, and the result was comparable with that by ICP-MS. This study offers new fundamental insights into Ca binding by nucleic acids and improved metal selectivity by having multiple cooperative metal binding sites. [Mh] Termos MeSH primário: Técnicas Biossensoriais Cálcio/análise Cálcio/metabolismo Técnicas de Química Analítica/métodos DNA Catalítico/metabolismo [Mh] Termos MeSH secundário: Sítios de Ligação Cálcio/química Técnicas de Química Analítica/normas DNA Catalítico/química Íons/metabolismo Limite de Detecção Água/química [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (DNA, Catalytic); 0 (Ions); 059QF0KO0R (Water); SY7Q814VUP (Calcium) [Em] Mês de entrada: 1707 [Cu] Atualização por classe: 170718 [Lr] Data última revisão: 170718 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170115 [St] Status: MEDLINE [do] DOI: 10.1002/cbic.201600708

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