Principles of Fluorescence Spectroscopy

PRINCIPLES OF FLUORESCENCE SPECTROSCOPY 227
Figure 6.41. Excimer formation by a self-assembled perylene diimide derivative. Revised and reprinted with permission from [89]. Copyright © 2003,
American Chemical Society. Courtesy of Dr. Alex D. Q. Li from the Washington State University.
weakly fluorescent in the absence of protein (Figure 6.43).
Addition of calmodulin, without calcium, had only a minor
effect on the emission. Addition of calcium to calmodulin
resulted in a dramatic increase in the intensity of the three
probes. Since the effect was seen with neutral (NPN), negatively
charged (ANS), and partially charged (9-AC)
probes, the binding was interpreted as due to hydrophobic
rather than electrostatic interactions between the probe and
calmodulin.
6.9.3. Binding to Cyclodextrin Using a
Dansyl Probe
While there are numerous examples of proteins labeled
with fluorescent probes, relatively few studies are available
using labeled carbohydrates. 98–99 The solvent sensitivity of
Figure 6.42. Emission spectra of acrylodan-labeled fatty acid binding
protein (FABP). The numbers refer to the concentration in µM of fatty
acid (oleate) added to 0.2-µM FABP. Revised from [90].