posted on 2020-11-07, 01:36authored bySamuel
P. Bernhard, Candace K. Goodman, Erienne G. Norton, Daniel G. Alme, C. Martin Lawrence, Mary J. Cloninger
Measuring the binding affinity for
proteins that can aggregate
or undergo complex binding motifs presents a variety of challenges.
In this study, fluorescence lifetime measurements using intrinsic
tryptophan fluorescence were performed to address these challenges
and to quantify the binding of a series of carbohydrates and carbohydrate-functionalized
dendrimers to recombinant human galectin-3. Collectively, galectins
represent an important target for study; in particular, galectin-3
plays a variety of roles in cancer biology. Galectin-3 binding dissociation
constants (KD) were quantified: lactoside
(73 ± 4 μM), methyllactoside (54 ± 10 μM), and
lactoside-functionalized G(2), G(4), and G(6)-PAMAM dendrimers (120
± 58 μM, 100 ± 45 μM, and 130 ± 25 μM,
respectively). The chosen examples showcase the widespread utility
of time-dependent fluorescence spectroscopy for determining binding
constants, including interactions for which standard methods have
significant limitations.