Time-Dependent Fluorescence Spectroscopy to Quantify Complex Binding Interactions


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.




Bernhard, Samuel P., Candace K. Goodman, Erienne G. Norton, Daniel G. Alme, C. Martin Lawrence, and Mary J. Cloninger. “Time-Dependent Fluorescence Spectroscopy to Quantify Complex Binding Interactions.” ACS Omega 5, no. 45 (November 6, 2020): 29017–29024. doi:10.1021/acsomega.0c03416.
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