Regulation of Rubisco in Arabidopsis Thaliana Rca(-) Complemented With Arabidopsis Rubisco Activase Engineered at an ATP Binding Site

106 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998.Q111E and Q111D showed rates of Rubisco activation greater than 42kD wild type and Q111S at ADP/ATP ratios known to exist in planta. Q111D showed a Rubisco activation rate at night time ADP/ATP greater than the 42kD wild type rate at zero ADP/ATP suggesting an altered response. Measurements of K$\rm\sb{d}$ ADP and K$\rm\sb{d}$ ATP with a fluorescent probe suggested that engineered Rubisco activase proteins have a reduced affinity for ATP and the inhibitor ADP. Transgenic plants expressing Q111D, Q111E, Q111S or 42kD wild type, showed a greater ability to activate Rubisco and an uncoupling of light regulation of Rubisco when compared to a wild type plant. This was unexpected since the 42kD wild type and engineered enzymes had shown different rates of Rubisco activation at in planta ADP/ATP. Since the 46kD isoform of Rubisco activase is expressed in the wild type and not in the transgenics, the results suggested that the 46kD isoform of Arabidopsis Rubisco activase may be a light regulatory component of Rubisco activation.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD