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Phylogenetic Engineering At An Interface Between Large And Small Subunits Imparts Land-Plant Kinetic Properties To Algal Rubisco, Robert J. Spreitzer, Srinivasa R. Peddi, Sriram Satagopan

Department of Biochemistry: Faculty Publications

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of photosynthetic CO₂ fixation and, thus, limits agricultural productivity. However, Rubisco enzymes from different species have different catalytic constants. If the structural basis for such differences were known, a rationale could be developed for genetically engineering an improved enzyme. Residues at the bottom of the large-subunit α/β-barrel active site of Rubisco from the green alga Chlamydomonas reinhardtii (methyl-Cys-256, Lys-258, and Ile-265) were previously changed through directed mutagenesis and chloroplast transformation to residues characteristic of land-plant Rubisco (Phe-256, Arg-258, and Val-265). The resultant enzyme has decreases in carboxylation efficiency and CO₂/O …