title: Chemical activation of the cyanobacterial orange carotenoid protein.
abstract: The effects of the Hofmeister series of ions on the activation of the orange carotenoid protein (OCP) from the inactive orange form to the active red form were tested. Kosmotropes led to lower OCP activation, whereas chaotropes led to greater OCP activation. Concentrations of thiocyanate exceeding 1.5M dark activate the orange carotenoid protein to its red form. This chemically activated OCP was studied by UV-vis and circular dichroism spectroscopies. The chemically-activated OCP quenches the fluorescence of phycobilisomes in vitro, to a level comparable to that of the light-activated OCP.
authors.affiliation: Graduate Program in Plant and Microbial Biosciences, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO 63130, United States.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: King
authors.affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO 63130, United States.
authors.forename: Haijun
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO 63130, United States.
authors.forename: Guannan
authors.initials: G
authors.lastname: He
authors.affiliation: Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO 63130, United States.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Orf
authors.affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States; Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO 63130, United States. Electronic address: Blankenship@wustl.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Blankenship
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D000458:Cyanobacteria; D003624:Darkness; D004305:Dose-Response Relationship, Drug; D045524:Phycobilisomes / Q000378:metabolism; D055550:Protein Stability / Q000187:drug effects; D012492:Salts / Q000494:pharmacology; D013861:Thiocyanates / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D045524:Phycobilisomes; D012492:Salts; D013861:Thiocyanates; C109473:orange carotenoid protein, Synechocystis; C031760:thiocyanate
keywords: Hofmeister series; Non-photochemical quenching; Orange carotenoid protein