title: Light-dependent chlorophyll f synthase is a highly divergent paralog of PsbA of photosystem II.
abstract: Chlorophyll f (Chl f) permits some cyanobacteria to expand the spectral range for photosynthesis by absorbing far-red light. We used reverse genetics and heterologous expression to identify the enzyme for Chl f synthesis. Null mutants of "super-rogue" psbA4 genes, divergent paralogs of psbA genes encoding the D1 core subunit of photosystem II, abolished Chl f synthesis in two cyanobacteria that grow in far-red light. Heterologous expression of the psbA4 gene, which we rename chlF, enables Chl f biosynthesis in Synechococcus sp. PCC 7002. Because the reaction requires light, Chl f synthase is probably a photo-oxidoreductase that employs catalytically useful Chl a molecules, tyrosine YZ, and plastoquinone (as does photosystem II) but lacks a Mn4Ca1O5 cluster. Introduction of Chl f biosynthesis into crop plants could expand their ability to use solar energy.
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA. Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Ming-Yang
authors.initials: MY
authors.lastname: Ho
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Gaozhong
authors.initials: G
authors.lastname: Shen
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Canniffe
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Chi
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA. Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802, USA. Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA. Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore. dab14@psu.edu.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Bryant
mesh_terms: D055162:Biocatalysis; D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000235:genetics; D018556:Crops, Agricultural / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005798:Genes, Bacterial; D008027:Light; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D010971:Plastoquinone / Q000737:chemistry; D055503:Protein Multimerization; D012993:Solar Energy; D046940:Synechococcus / Q000201:enzymology* / Q000235:genetics; D014443:Tyrosine / Q000737:chemistry; D014867:Water / Q000378:metabolism
chemical_list: D045332:Photosystem II Protein Complex; C583352:chlorophyll f; C422369:photosystem II, psbA subunit; D014867:Water; D002734:Chlorophyll; D014443:Tyrosine; D010088:Oxidoreductases; D010971:Plastoquinone