Ribulose-1,5-bisphosphate carboxylase/oxygenase activase isoforms from diverse species show differences in oligomeric structure, thermal stability, and activity.

ABSTRACT: Rubisco activase (Rca) is critical for maintaining Rubisco activity during photosynthesis by removing inhibitory sugar phosphates through ATP hydrolysis. Despite its importance, the structural and functional diversity of Rca across species remain poorly understood. This study compares the oligomeric assembly, thermal stability, and functional activities of α- and β-isoforms of Rca from cotton, creosote, Antarctic hairgrass, and Sitka spruce, representing diverse thermal and ecological adaptations. We found that cotton and creosote Rca isoforms form highly polydisperse complexes in solution, with no evidence of discrete hexamer formation, even in the presence of Mg.ATPγS. In contrast, Antarctic hairgrass α-Rca and Sitka spruce β-Rca formed stable hexamers under similar conditions. Spruce α-

SUBMITTER: Keown JR 

PROVIDER: S-EPMC12552412 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature