Catalytic by-product formation and ligand binding by ribulose bisphosphate carboxylases from different phylogenies.

摘要: During catalysis, all Rubisco (D-ribulose-1,5-bisphosphate carboxylase/oxygenase) enzymes produce traces of several by-products. Some these by-products are released slowly from the active site higher plants, thus progressively inhibiting turnover. Prompted by observations that Form I cyanobacteria and red algae, II enzyme bacteria, do not show inhibition over time, production binding catalytic was measured to ascertain underlying differences. In present study we IB cyanobacterium Synechococcus PCC6301, ID alga Galdieria sulfuraria low-specificity type bacterium Rhodospirillum rubrum catalyse formation varying degrees; however, inhibitory under substrate-saturated conditions. Study release phosphorylated analogues substrate or reaction intermediates revealed diverse strategies for avoiding inhibition. R. have an increased rate inhibitor release. G. releases inhibitors very slowly, but has constant maintains in activated state. These may provide information about dynamics, degree flexibility. Our also illustrate phylogenetic diversity mechanisms regulating raise questions whether activase-like mechanism should be expected outside green-algal/higher-plant lineage.