| Autor: |
Kuchlyan J; Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France., Martinez-Fernandez L; Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemistry (IADCHEM), Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid, Spain., Mori M; Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy., Gavvala K; Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France., Ciaco S; Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France.; Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy., Boudier C; Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France., Richert L; Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France., Didier P; Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France., Tor Y; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States., Improta R; Consiglio Nazionale delle Ricerche, Istituto Biostrutture e Bioimmagini, Via Mezzocannone 16, 80134 Napoli, Italy., Mély Y; Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France. |
| Abstrakt: |
Thienoguanosine ( th G) is an isomorphic guanosine (G) surrogate that almost perfectly mimics G in nucleic acids. To exploit its full potential and lay the foundation for future applications, 20 DNA duplexes, where the bases facing and neighboring th G were systematically varied, were thoroughly studied using fluorescence spectroscopy, molecular dynamics simulations, and mixed quantum mechanical/molecular mechanics calculations, yielding a comprehensive understanding of its photophysics in DNA. In matched duplexes, th G's hypochromism was larger for flanking G/C residues but its fluorescence quantum yield (QY) and lifetime values were almost independent of the flanking bases. This was attributed to high duplex stability, which maintains a steady orientation and distance between nucleobases, so that a similar charge transfer (CT) mechanism governs the photophysics of th G independently of its flanking nucleobases. th G can therefore replace any G residue in matched duplexes, while always maintaining similar photophysical features. In contrast, the local destabilization induced by a mismatch or an abasic site restores a strong dependence of th G's QY and lifetime values on its environmental context, depending on the CT route efficiency and solvent exposure of th G. Due to this exquisite sensitivity, th G appears ideal for monitoring local structural changes and single nucleotide polymorphism. Moreover, th G's dominant fluorescence lifetime in DNA is unusually long (9-29 ns), facilitating its selective measurement in complex media using a lifetime-based or a time-gated detection scheme. Taken together, our data highlight th G as an outstanding emissive substitute for G with good QY, long fluorescence lifetimes, and exquisite sensitivity to local structural changes. |
