Mutation in the cysteine bridge domain of the gamma-subunit affects light regulation of the ATP synthase but not photosynthesis or growth in Arabidopsis.
The chloroplast ATP synthase synthesizes ATP from ADP and free phosphate coupled by the electrochemical potential across the thylakoid membrane in the light. The light-dependent regulation of ATP synthase activity is carried out in part through redox modulation of a cysteine disulfide bridge in CF1 gamma-subunit. In order to investigate the function of the redox regulatory domain and the physiological significance of redox modulation for higher plants, we designed four mutations in the redox regulatory domain of the gamma-subunit to create functional mimics of the permanently reduced form of the gamma-subunit. While the inability to reduce the regulatory disulfide results in lower photosynthesis and growth, unexpectedly, the results reported here show that inability to reoxidize the dithiol may not be of any direct detriment to plant photosynthetic performance or growth.
Department of Plant Biology, University of Illinois, 1201 W. Gregory Dr., Urbana, IL 61801, USA.
Guosheng
G
Wu
Donald R
DR
Ort
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D025222:Chloroplast Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D007700:Kinetics; D008027:Light; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010788:Photosynthesis; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D021122:Protein Subunits; D025222:Chloroplast Proton-Translocating ATPases; D003545:Cysteine