Abstract
Non-photosynthetic bacteria, B. subtilis possesses the gene coding RLP similar to RuBisCO. RLP is predicted to function in the methionine salvage pathway (MSP), because the RLP gene is located in the MSP operon. The reaction steps and enzymes in this pathway were identified to elucidate the catalyzing reaction of RLP by 1H-NMR and UV-visible spectroscopy using recombinant RLP, ykrS, X, Y, Z coded in MSP operons. This analysis revealed that RLP catalyzes 2,3-diketo-5-methylthiopentane-1-phosphate enolase reaction in the fourth step in the MSP. Enolization of ketose-phosphate is also catalyzed by photosynthetic RuBisCO. Furthermore, although RLP deletion mutant could not grow on the medium containing methylthioadenosine, the initial metabolite in the MSP as a sole sulfur compound, the mutant rescued by introducing the photosynthetic bacteria Rhodspillirum rubrum rbcL gene. This result shows that photosynthetic RuBisCO and RLP have the ability to catalyze the same reaction.
