title: Biochemical characterization of predicted Precambrian RuBisCO.
abstract: The antiquity and global abundance of the enzyme, RuBisCO, attests to the crucial and longstanding role it has played in the biogeochemical cycles of Earth over billions of years. The counterproductive oxygenase activity of RuBisCO has persisted over billions of years of evolution, despite its competition with the carboxylase activity necessary for carbon fixation, yet hypotheses regarding the selective pressures governing RuBisCO evolution have been limited to speculation. Here we report the resurrection and biochemical characterization of ancestral RuBisCOs, dating back to over one billion years ago (Gyr ago). Our findings provide an ancient point of reference revealing divergent evolutionary paths taken by eukaryotic homologues towards improved specificity for CO2, versus the evolutionary emphasis on increased rates of carboxylation observed in bacterial homologues. Consistent with these distinctions, in vivo analysis reveals the propensity of ancestral RuBisCO to be encapsulated into modern-day carboxysomes, bacterial organelles central to the cyanobacterial CO2 concentrating mechanism.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Shih
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Occhialini
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, USA.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Cameron
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.
authors.forename: P John
authors.initials: PJ
authors.lastname: Andralojc
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.|Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1, 4YQ, UK.
authors.forename: Martin A J
authors.initials: MA
authors.lastname: Parry
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, USA.|Department of Biochemistry and Molecular Biology, DOE Plant Research Laboratories, Michigan State University, East Lansing, Michigan 488242, USA.|Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Kerfeld
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D012273:Ribulose-Bisphosphate Carboxylase