Energy-dependent conformational changes in the epsilon subunit of the chloroplast ATP synthase (CF0CF1).
Incubation of spinach chloroplast thylakoids with pyridoxal 5'-phosphate modified the epsilon subunit of ATP synthase (CF0CF1). Illumination of thylakoids stimulated the modification of one specific amino acid residue of the epsilon subunit by a factor of 3. Endoproteinase Glu-C treatment of the isolated epsilon subunit and fractionation of the peptides by high performance liquid chromatography revealed a major fluorescent peptide with the sequence GKRQKIE. Further treatment of this peptide with endoproteinase Arg-C gave a strongly fluorescent tripeptide (GXR). From the primary structure of the epsilon subunit, the specifically modified residue was deduced to be Lys-109. This suggests the energy-dependent conformational changes in the epsilon subunit which change the surroundings of Lys-109 and alter the reactivity of this residue.
Komatsu-Takaki
M
M
Department of Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan.
D000595:Amino Acid Sequence; D002736:Chloroplasts / Q000201:enzymology*; D004735:Energy Transfer; D008239:Lysine; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D010944:Plants / Q000201:enzymology; D011487:Protein Conformation; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D013050:Spectrometry, Fluorescence
D046911:Macromolecular Substances; D010446:Peptide Fragments; D011732:Pyridoxal Phosphate; D006180:Proton-Translocating ATPases; D008239:Lysine