title: Rubisco small subunits from the unicellular green alga Chlamydomonas complement Rubisco-deficient mutants of Arabidopsis.
abstract: Introducing components of algal carbon concentrating mechanisms (CCMs) into higher plant chloroplasts could increase photosynthetic productivity. A key component is the Rubisco-containing pyrenoid that is needed to minimise CO2retro-diffusion for CCM operating efficiency. Rubisco in Arabidopsis was re-engineered to incorporate sequence elements that are thought to be essential for recruitment of Rubisco to the pyrenoid, namely the algal Rubisco small subunit (SSU, encoded by rbcS) or only the surface-exposed algal SSU α-helices. Leaves of Arabidopsis rbcs mutants expressing 'pyrenoid-competent' chimeric Arabidopsis SSUs containing the SSU α-helices from Chlamydomonas reinhardtii can form hybrid Rubisco complexes with catalytic properties similar to those of native Rubisco, suggesting that the α-helices are catalytically neutral. The growth and photosynthetic performance of complemented Arabidopsis rbcs mutants producing near wild-type levels of the hybrid Rubisco were similar to those of wild-type controls. Arabidopsis rbcs mutants expressing a Chlamydomonas SSU differed from wild-type plants with respect to Rubisco catalysis, photosynthesis and growth. This confirms a role for the SSU in influencing Rubisco catalytic properties.
authors.affiliation: SynthSys & Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
authors.forename: Nicky
authors.initials: N
authors.lastname: Atkinson
authors.affiliation: Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Nuno
authors.identifier: http://orcid.org/0000-0002-8802-5215
authors.initials: N
authors.lastname: Leitão
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
authors.forename: Douglas J
authors.identifier: http://orcid.org/0000-0003-1217-537X
authors.initials: DJ
authors.lastname: Orr
authors.affiliation: Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK.
authors.forename: Moritz T
authors.initials: MT
authors.lastname: Meyer
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
authors.forename: Elizabete
authors.initials: E
authors.lastname: Carmo-Silva
authors.affiliation: Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK.
authors.forename: Howard
authors.initials: H
authors.lastname: Griffiths
authors.affiliation: Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Smith
authors.affiliation: SynthSys & Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.|Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Alistair J
authors.identifier: http://orcid.org/0000-0002-7255-872X
authors.initials: AJ
authors.lastname: McCormick
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D055162:Biocatalysis; D002696:Chlamydomonas / Q000201:enzymology*; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D007527:Isoenzymes / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D010940:Plant Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D002734:Chlorophyll; D012273:Ribulose-Bisphosphate Carboxylase
keywords: 
  Arabidopsis thaliana
  ; 
  Chlamydomonas reinhardtii
  ; Rubisco; carbon concentrating mechanism (CCM); chloroplast; photosynthesis; pyrenoid; tobacco