title: A fluorometric study with 1-anilinonaphthalene-8-sulfonic acid (ANS) of the interactions of ATP and ADP with rubisco activase.
abstract: The interactions of ATP and ADP with rubisco activase purified from spinach were investigated by measuring enhanced fluorescence due to ANS-binding to the protein. Evidence of conformational changes was observed from the differences in the interaction of ANS with rubisco activase in the presence of excess ATP and ADP. Fluorescent changes associated with the titration of a rubisco activase-ANS mixture with ATP and ADP indicated that the binding of ADP to rubisco activase was much tighter than that of ATP. The concentration of Mg2+ and pH had significant effects on the affinities of rubisco activase for ATP and ADP, with higher pH and Mg2+ concentration facilitating the binding of ATP to rubisco activase in the presence of ADP. The physiological implications of the binding characteristics of ATP and ADP with rubisco activase on the light-dark regulation of rubisco are discussed.
authors.affiliation: Department of Agronomy, University of Illinois, Champaign-Urbana.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Wang
authors.forename: A R
authors.initials: AR
authors.lastname: Portis
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D010940:Plant Proteins; D010944:Plants / Q000201:enzymology*; D012273:Ribulose-Bisphosphate Carboxylase / Q000302:isolation & purification / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D010940:Plant Proteins; C054765:rca protein, plant; D015636:Magnesium Chloride; D000244:Adenosine Diphosphate; C027132:1-anilino-8-naphthalenesulfonate; D000255:Adenosine Triphosphate; D012273:Ribulose-Bisphosphate Carboxylase