RESUMO
We present a simple strategy for the synthesis of main chain oligonucleotide rotaxanes with precise control over the position of the macrocycle. The novel DNA-based rotaxanes were analyzed to assess the effect of the mechanical bond on their properties.
Assuntos
Cobre/química , DNA/síntese química , Oligonucleotídeos/síntese química , Rotaxanos/síntese química , Alcinos/síntese química , Alcinos/química , Azidas/síntese química , Azidas/química , Química Click , Reação de Cicloadição , DNA/química , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/química , Oligonucleotídeos/química , Rotaxanos/químicaRESUMO
Porphyrins were attached to LNA uridine building blocks via rigid 5-acetylene or more flexible propargyl-amide linkers and incorporated into DNA strands. The systems show a greatly increased thermodynamic stability when using as little as three porphyrins in a zipper arrangement. Thermodynamic analysis reveals clustering of the strands into more ordered duplexes with both greater negative ΔΔS and ΔΔH values, and less ordered duplexes with small positive ΔΔS differences, depending on the combination of linkers used. The exciton coupling between the porphyrins is dependent on the flanking DNA sequence in the single stranded form, and on the nature of the linker between the nucleobase and the porphyrin in the double stranded form; it is, however, also strongly influenced by intermolecular interactions. This system is suitable for the formation of stable helical chromophore arrays with sequence and structure dependent exciton coupling.
Assuntos
Oligonucleotídeos/química , Compostos Organometálicos/química , Porfirinas/química , Dicroísmo Circular , Estrutura Molecular , Termodinâmica , Zinco/químicaRESUMO
HyBeacon probes have been used to characterise SNPs in the CYP2C9 and VKORC1 genes associated with variations in the efficiency of warfarin metabolism. PCR amplification of genomic DNA and probe target melting analysis provided a robust and reliable method to differentiate polymorphic sequences at these loci. Probes capped with 5'-trimethoxystilbene were found to exhibit larger fluorescence differences between hybridised and dissociated states than uncapped probes, generating melting peaks of considerably improved height. 3'-Pyrene modifications enhanced probe signal-to-noise and melting peak heights with the additional benefit of acting as PCR stoppers, and 5',3'-doubly capped probes gave the best analytical results.
Assuntos
Corantes Fluorescentes/química , Sondas de Oligonucleotídeos/química , Polimorfismo Genético , Varfarina/metabolismo , Hidrocarboneto de Aril Hidroxilases/genética , Citocromo P-450 CYP2C9 , DNA/genética , DNA/metabolismo , Genótipo , Humanos , Oxigenases de Função Mista/genética , Reação em Cadeia da Polimerase/métodos , Vitamina K Epóxido RedutasesRESUMO
We report the use of Co-porphyrins as electrochemical tags for a highly sensitive and selective genosensor. An avian influenza virus-based DNA sequence characteristic of H5N1 was detected at femtomolar levels from competing non-complementary sequences through hybridisation with the labeled DNA.
Assuntos
Técnicas Biossensoriais , Sondas de DNA/química , DNA Viral/análise , Eletroquímica/instrumentação , Virus da Influenza A Subtipo H5N1/genética , Porfirinas/química , Animais , Sondas de DNA/genética , DNA Viral/genética , Eletroquímica/métodos , Eletrodos , Ouro/química , Hibridização de Ácido NucleicoRESUMO
A programmable switch based on a DNA hairpin loop is functionalised with a rigid or flexible porphyrin or FAM and TAMRA FRET pair, which provides insight into the restructuring of the hairpin as well as porphyrin-porphyrin coupling. The switch contains five discrete states which can be accessed independently and followed by real-time spectroscopy, opening the way to a quinary computing code.