A Functional Link Between RuBisCO-like Protein of Bacillus and Photosynthetic RuBisCO

Abstract

The genomes of several nonphotosynthetic bacteria, such as Bacillus subtilis , and some Archaea include genes for proteins with sequence homology to the large subunit of ribulose bisphosphate carboxylase/oxygenase (RuBisCO). We found that such a RuBisCO-like protein (RLP) from B. subtilis catalyzed the 2,3-diketo-5-methylthiopentyl-1-phosphate enolase reaction in the methionine salvage pathway. A growth-defective mutant, in which the gene for this RLP had been disrupted, was rescued by the gene for RuBisCOfrom the photosynthetic bacterium Rhodospirillum rubrum . Thus, the photosynthetic RuBisCO from R. rubrum retains the ability to function in the methionine salvage pathway in B. subtilis .