RT Journal Article
SR Electronic
T1 Temperature response of Rubisco kinetics in <em>Arabidopsis thaliana</em>: thermal breakpoints and implications for reaction mechanisms
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 320879
DO 10.1101/320879
A1 Boyd, Ryan A.
A1 Cavanagh, Amanda P.
A1 Kubien, David S.
A1 Cousins, Asaph B.
YR 2018
UL http://biorxiv.org/content/early/2018/05/13/320879.abstract
AB Optimization of Rubisco kinetics could improve photosynthetic efficiency, ultimatly resulting in increased crop yield. However, imprecise knowledge of the reaction mechanism and the individual rate constants limit our ability to optimize the enzyme. Membrane inlet mass spectrometery (MIMS) may offer benefits over traditional methods for determining individual rate constants of the Rubisco reaction mechanism, as it can directly monitor concentration changes in CO2, O2, and their isotopologs during assays. However, a direct comparsion of MIMS to the traditional Radiolabel method of determining Rubisco kinetic parameters has not been made. Here, the temperature responses of Rubisco kinetic parameters from Arabidopsis thaliana were measured using the Radiolabel and MIMS methods. The two methods provided comparable parameters above 25 °C, but temperature responses deviated at low temperature as MIMS derived catalytic rates of carboxylation, oxygenation, and CO2/O2 specificity showed thermal breakpoints. Here we discuss the variability and uncertainty surrounding breakpoints in the Rubisco temperature response and relavance of individual rate constants of the reaction mechanisms to potential breakpoints.