The dimerization of folded monomers of ribulose 1,5-bisphosphate carboxylase/oxygenase.
Spontaneous refolding and reconstitution processes of dimeric ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) from Rhodospirillum rubrum have been investigated using size-exclusion high performance liquid chromatography (HPLC), spectroscopic, and activity measurements. When the unfolded Rubisco in guanidine hydrochloride is diluted at 4 degrees C, a folding intermediate (Rubisco-I) is rapidly formed, which remains in an unstable monomeric state and gradually develops into folded monomer (Rubisco-M) at 4 degrees C but undergoes irreversible aggregation at 25 degrees C. Refolding of Rubisco-I to Rubisco-M is a very slow process, taking about 20 h for 70% conversion at 4 degrees C. Rubisco-M is stable at 4 degrees C and is capable of forming an active dimer spontaneously when incubated at a temperature higher than 10 degrees C. The dynamic dimerization process has been measured in a temperature range of 4-35 degrees C by HPLC, and the results demonstrate that the dimerization is strongly facilitated by the temperature. It is found that dithiothreitol is essential for the spontaneous reconstitution of Rubisco.
Luo
S
S
Department of Biomolecular Engineering, Faculty of Engineering, Center for Interdisciplinary Research, Tohoku University, Sendai 980-8579, Japan.
Wang
Z Y
ZY
Kobayashi
M
M
Nozawa
T
T
D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D019281:Dimerization; D008027:Light; D017510:Protein Folding; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry* / Q000378:metabolism; D012542:Scattering, Radiation; D013053:Spectrophotometry; D013696:Temperature; D013997:Time Factors
D012273:Ribulose-Bisphosphate Carboxylase