title: Selective modification of an alpha subunit of chloroplast coupling factor 1.
abstract: Lucifer yellow (4-amino-N-[3-(vinylsulfonyl)phenyl]naphthalimide-3,6-disulf onate), a fluorescent probe that can react covalently with sulfhydryl or amino groups, has been used to modify chloroplast coupling factor 1 (CF1). Conditions are described under which Lucifer yellow selectively labels the alpha subunit of CF1 to the extent of about 1 mol of probe per mole of CF1. An especially reactive amino group is apparently labeled, and modification has little effect on the ATPase activity of the enzyme. Lucifer yellow is a useful probe for fluorescence energy transfer measurements. The distances between this probe and fluorescent and absorbing molecules attached to seven specific sites on the beta, gamma, and epsilon subunits were determined. These distances converge to a single location. In addition to providing further information about the structure of CF1, these results suggest that the alpha subunits of CF1 are not structurally equivalent.
authors.forename: C M
authors.initials: CM
authors.lastname: Nalin
authors.forename: B
authors.initials: B
authors.lastname: Snyder
authors.forename: R E
authors.initials: RE
authors.lastname: McCarty
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004735:Energy Transfer; D007546:Isoquinolines; D046911:Macromolecular Substances; D008433:Mathematics; D010446:Peptide Fragments / Q000032:analysis; D006180:Proton-Translocating ATPases / Q000032:analysis*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D007546:Isoquinolines; D046911:Macromolecular Substances; D010446:Peptide Fragments; C017475:lucifer yellow; D006180:Proton-Translocating ATPases