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Titolo:
Probing the structure and dynamics of a DNA hairpin by ultrafast quenchingand fluorescence depolarization
Autore:
Larsen, OFA; van Stokkum, IHM; Gobets, B; van Grondelle, R; van Amerongen, H;
Indirizzi:
Free Univ Amsterdam, Fac Sci, Div Phys & Astron, NL-1081 HV Amsterdam, Netherlands Free Univ Amsterdam Amsterdam Netherlands NL-1081 HV terdam, Netherlands
Titolo Testata:
BIOPHYSICAL JOURNAL
fascicolo: 2, volume: 81, anno: 2001,
pagine: 1115 - 1126
SICI:
0006-3495(200108)81:2<1115:PTSADO>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXCITATION-ENERGY TRANSFER; REV RESPONSIVE ELEMENT; ELECTRON-TRANSFER; CONFORMATIONAL DYNAMICS; 2-AMINOPURINE; SPECTROSCOPY; DISTANCE; PROTEIN; BINDING; SITE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Larsen, OFA Free Univ Amsterdam, Fac Sci, Div Phys & Astron, De Boelelaan 1081, NL-1081 HV Amsterdam, Netherlands Free Univ Amsterdam De Boelelaan 1081 Amsterdam Netherlands NL-1081 HV
Citazione:
O.F.A. Larsen et al., "Probing the structure and dynamics of a DNA hairpin by ultrafast quenchingand fluorescence depolarization", BIOPHYS J, 81(2), 2001, pp. 1115-1126

Abstract

DNA hairpins have been investigated in which individual adenines were replaced by their fluorescent analog 2-aminopurine (2AP). The temperature dependence of the time evolution of polarized emission spectra was monitored with picosecond time resolution. Four isotropic decay components for each oligonucleotide indicated the coexistence of at least four conformations. The fluorescence for three of these was significantly quenched, which is explained by hole transfer from 2AP to guanine(s). An similar to8-ps component is ascribed to direct hole transfer, the similar to 50-ps and similar to 500-ps components are ascribed to structural reorganization, preceding hole transfer. At room temperature, a fraction remains unquenched on a 10-ns timescale, in contrast to higher temperatures, where the flexibility increases. Besides quenching due to base stacking, a second quenching process was neededto describe the data. Evidence for both intrastrand and interstrand hole transfer was found. The extracted probability for stacking between neighboring bases in double-stranded regions was estimated to be similar to 75% at room temperature and similar to 25% at 80 degreesC, demonstrating structuraldisorder of the DNA. Fluorescence depolarization revealed both local dynamics of the DNA and overall dynamics of the entire oligonucleotide. Upon raising the temperature, the C-N terminus of the hairpin appears to melt first; the rest of the hairpin denatures above the average melting temperature.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/03/20 alle ore 23:38:42