Dimer formation of organic fluorophores reports on biomolecular dynamics under denaturing conditions

作者：Bollmann Stefan; Loellmann Marc; Sauer Markus; Doose Soeren^*

来源：Physical Chemistry Chemical Physics, 2011, 13(28): 12874-12882.

DOI：10.1039/c1cp21111k

Stacking interactions between organic fluorophores can cause formation of non-fluorescent H-dimers. Dimer formation and dissociation of two fluorophores site-specifically incorporated in a biomolecule result in fluorescence intermittency that can report on conformational dynamics. We characterize intramolecular dimerization of two oxazine fluorophores MR121 attached to an unstructured polypeptide. Formation of stable non-fluorescent complexes with nano- to microsecond lifetimes is a prerequisite for analysing the intermittent fluorescence emission by fluorescence correlation spectroscopy and extracting relaxation time constants on nano- to millisecond time scales. Destabilization of the generally very stable homodimers by chemical denaturation reduces the lifetime of H-dimers. We demonstrate that H-dimer formation of an oxazine fluorophore reports on end-to-end contact rates in unstructured glycine-serine polypeptides under denaturing conditions.

• 出版日期2011