Deciphering the pH-dependence of ground- and excited-state equilibria of thienoguanine.

ABSTRACT: The thienoguanine nucleobase (^thG_b) is an isomorphic fluorescent analogue of guanine. In aqueous buffer at neutral pH, ^thG_b exists as a mixture of two ground-state H1 and H3 keto-amino tautomers with distinct absorption and emission spectra and high quantum yield. In this work, we performed the first systematic photophysical characterization of ^thG_b as a function of pH (2 to 12). Steady-state and time-resolved fluorescence spectroscopies, supplemented with theoretical calculations, enabled us to identify three additional ^thG_b forms, resulting from pH-dependent ground-state and excited-state reactions. Moreover, a thorough analysis allowed us to retrieve their individual absorption and emission spectra a

SUBMITTER: Didier P 

PROVIDER: S-EPMC7335457 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature