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

A capillary electrophoresis method was developed to observe the dissociatio n of Rubisco, which is a hexadecamer enzyme with a molecular weight of ca. 560 kDa. In contrast to the normal separation mode in capillary electrophor esis, a minimum constant pressure together with a constant electric voltage was used to perform the separation of Rubisco. Based on this new separatio n mode, the conformational change during the dissociation was also observed in vivo by capillary electrophoresis. The equilibrium conditions of the di ssociation were determined and the dynamics of the dissociation were studie d 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 observatio n of dissociation, the metastable state of the conformation of Rubisco olig omer was observed by capillary electrophoresis. Moreover, the stability of Rubisco under different conditions was examined, and it was demonstrated th at freeze-thawing could result in dissociation.