55F. Bezanilla () · M. Priest
Department of Biochemistry and Molecular Biology and Committee on Neurobiology,
University of Chicago, Gordon Center for Integrative Science W229M, 929 East 57th Street,
Chicago, IL 60637, USA
e-mail: [email protected]
M. Priest
e-mail: [email protected]
Functional Site-Directed Fluorometry
Michael Priest and Francisco Bezanilla
Abstract Initially developed in the mid-1990s to examine the conformational
changes of the canonical Shaker voltage-gated potassium channel, functional site-
directed fluorometry has since been expanded to numerous other voltage-gated and
ligand-gated ion channels as well as transporters, pumps, and other integral mem-
brane proteins. The power of functional site-directed fluorometry, also known as
voltage-clamp fluorometry, lies in its ability to provide information on the confor-
mational changes in a protein in response to changes in its environment with high
temporal resolution while simultaneously monitoring the function of that protein.
Over time, applications of site-directed fluorometry have expanded to examine the
interactions of ion channels with modulators ranging from membrane potential to
ligands to accessory protein subunits to lipids. In the future, the range of ques-
tions answerable by functional site-directed fluorometry and its interpretive power
should continue to improve, making it an even more powerful technique for dis-
secting the conformational dynamics of ion channels and other membrane proteins.
Keywords Site-directed fluorometry · Voltage-clamp fluorometry · Conformational
dynamics · Voltage-gated ion channels · Ligand-gated ion channels · Fluorescent
dye · Conformational change
© Springer Science+Business Media New York 2015
C. Ahern, S. Pless (eds.), Novel Chemical Tools to Study Ion Channel Biology,
Advances in Experimental Medicine and Biology 869,
DOI 10.1007/978-1-4939-2845-3_4