Dissociation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) observed by capillary electrophoresis

Abstract

A capillary electrophoresis method was developed to observe the dissociation of Rubisco, which is a hexadecamer enzyme with a molecular weight of ca. 560 kDa. In contrast to the normal separation mode in capillary electrophoresis, a minimum constant pressure together with a constant electric voltage was used to perform the separation of Rubisco. Based on this new separation mode, the conformational change during the dissociation was also observed in vivo by capillary electrophoresis. The equilibrium conditions of the dissociation were determined and the dynamics of the dissociation were studied in detail. It was found that the dissociation of Rubisco was completed in 4 min with the use of 0.4 mM sodium dodecyl sulfate. During the observation of dissociation, the metastable state of the conformation of Rubisco oligomer was observed by capillary electrophoresis. Moreover, the stability of Rubisco under different conditions was examined, and it was demonstrated that freeze–thawing could result in dissociation.