Applying 6-methylisoxanthopterin-enhanced fluorescence to examine protein-DNA interactions in the picomolar range.

ABSTRACT: Incorporation of fluorescent nucleoside analogues into duplex DNA usually leads to a reduction in quantum yield, which significantly limits their potential use and application. We have identified two pentamer DNA sequences containing 6-methylisoxanthopterin (6-MI) (ATFAA and AAFTA, where F is 6-MI) that exhibit significant enhancement of fluorescence upon formation of duplex DNA with quantum yields close to that of monomeric 6-MI. The enhanced fluorescence dramatically increases the utility and sensitivity of the probe and is used to study protein-DNA interactions of nanomolar specificity in this work. The increased sensitivity of 6-MI allows anisotropy binding measurements to be performed at DNA concentrations of 1 nM and fluorescence intensity measurements at 50 pM DNA. The ATFAA sequenc

SUBMITTER: Moreno A 

PROVIDER: S-EPMC3462076 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature