Time-resolved fluorescence of 2-aminopurine as a probe of base flipping in M.HhaI-DNA complexes.

ABSTRACT: DNA base flipping is an important mechanism in molecular enzymology, but its study is limited by the lack of an accessible and reliable diagnostic technique. A series of crystalline complexes of a DNA methyltransferase, M.HhaI, and its cognate DNA, in which a fluorescent nucleobase analogue, 2-aminopurine (AP), occupies defined positions with respect the target flipped base, have been prepared and their structures determined at higher than 2 A resolution. From time-resolved fluorescence measurements of these single crystals, we have established that the fluorescence decay function of AP shows a pronounced, characteristic response to base flipping: the loss of the very short (approximately 100 ps) decay component and the large increase in the amplitude of the long (approximately 10 ns) comp

SUBMITTER: Neely RK 

PROVIDER: S-EPMC1310896 | biostudies-literature | 2005

REPOSITORIES: biostudies-literature