title: Fiber optic sensor for Ca2+ based on an induced change in the conformation of the protein calmodulin.
abstract: A fiber optic sensor that exploits the natural selectivity of the Ca(2+)-binding protein calmodulin (CaM) is described. In this sensor, a dialysis membrane is used to entrap a fluorescein-labeled CaM (F-CaM) solution at the common end of a bifurcated fiber optic bundle. Ca2+ ions in a sample solution can diffuse through the membrane and bind to the F-CaM. Upon binding with Ca2+, CaM undergoes a conformational change that induces a change in the fluorescence of the attached fluorescein tag. This change in fluorescence can be related to the concentration of Ca2+ in the sample solution. The detection limit for the sensor is 5 x 10(-8) M Ca2+. The sensor has no interference by Mg2+ at concentrations as high as 10(-2) M.
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington 40506-0055.
authors.forename: T L
authors.initials: TL
authors.lastname: Blair
authors.forename: S T
authors.initials: ST
authors.lastname: Yang
authors.forename: T
authors.initials: T
authors.lastname: Smith-Palmer
authors.forename: L G
authors.initials: LG
authors.lastname: Bachas
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002118:Calcium / Q000032:analysis*; D002147:Calmodulin / Q000737:chemistry*; D002417:Cattle; D005336:Fiber Optic Technology; D005453:Fluorescence; D055100:Optical Fibers; D011487:Protein Conformation
chemical_list: D002147:Calmodulin; D002118:Calcium