posted on 2014-07-16, 00:00authored byJiun-Jie Shie, Ying-Chih Liu, Yu-Ming Lee, Carmay Lim, Jim-Min Fang, Chi-Huey Wong
We
have designed a low fluorescent azido-BODIPY-based probe AzBOCEt
(Az10) that undergoes copper(I)-catalyzed 1,3-dipolar
cycloadditions with alkynes to yield strongly fluorescent triazole
derivatives. The fluorescent quantum yield of a triazole product T10 is enhanced by 52-fold as compared to AzBOCEt upon excitation
at a wavelength above 500 nm. Quantum mechanical calculations indicate
that the increase in fluorescence upon triazole formation is due to
the lowering of the HOMO energy level of the aryl moiety to reduce
the process of acceptor photoinduced electron transfer. AzBOCEt is
shown to label alkyne-functionalized proteins in vitro and glycoproteins
in cells with excellent selectivity, and enables cell imaging and
visualization of glycoconjugates in alkynyl-saccharide-treated cells
at extremely low concentration (0.1 μM). Furthermore, the alkyne-tagged
glycoproteins from cell lysates can be directly detected with AzBOCEt
in gel electrophoresis.