title: Calmodulin, conformational states, and calcium signaling. A single-molecule perspective.
abstract: Single-molecule fluorescence measurements can provide a new perspective on the conformations, dynamics, and interactions of proteins. Recent examples are described illustrating the application of single-molecule fluorescence spectroscopy to calcium signaling proteins with an emphasis on the new information available in single-molecule fluorescence burst measurements, resonance energy transfer, and polarization modulation methods. Calcium signaling pathways are crucial in many cellular processes. The calcium binding protein calmodulin (CaM) serves as a molecular switch to regulate a network of calcium signaling pathways. Single-molecule spectroscopic methods can yield insights into conformations and dynamics of CaM and CaM-regulated proteins. Examples include studies of the conformations and dynamics of CaM, binding of target peptides, and interaction with the plasma-membrane Ca2+ pump. Single-molecule resonance energy transfer measurements revealed conformational substates of CaM, and single-molecule polarization modulation spectroscopy was used to probe interactions between CaM and the plasma-membrane Ca2+-ATPase.
authors.affiliation: Department of Chemistry, 1251 Wescoe Drive, University of Kansas, Lawrence, Kansas 66045-7582, USA. ckjohnson@ku.edu
authors.forename: Carey K
authors.initials: CK
authors.lastname: Johnson
mesh_terms: D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D020013:Calcium Signaling; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism*; D008968:Molecular Conformation; D013379:Substrate Specificity
chemical_list: D002147:Calmodulin; D000252:Calcium-Transporting ATPases; D002118:Calcium