title: Elucidation of the preferred routes of C8-vinyl reduction in chlorophyll and bacteriochlorophyll biosynthesis.
abstract: Most of the chlorophylls and bacteriochlorophylls utilized for light harvesting by phototrophic organisms carry an ethyl group at the C8 position of the molecule, the product of a C8-vinyl reductase acting on a chlorophyll/bacteriochlorophyll biosynthetic precursor. Two unrelated classes of C8-vinyl reductase are known to exist, BciA and BciB, found in the purple phototroph Rhodobacter sphaeroides and the cyanobacterium Synechocystis sp. PCC6803 respectively. We constructed strains of each bacterium with the native C8-vinyl reductase swapped for the other class of the enzyme, and combined these replacements with a series of deletions of the native bch and chl genes. In vivo data indicate that the preferred substrates for both classes of the enzyme is C8-vinyl chlorophyllide, with C8-vinyl protochlorophyllide reduced only under conditions in which this pigment accumulates as a result of perturbed formation of chlorophyllide.
authors.affiliation: *Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Canniffe
authors.affiliation: *Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
authors.forename: Jack W
authors.initials: JW
authors.lastname: Chidgey
authors.affiliation: *Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
authors.forename: C Neil
authors.initials: CN
authors.lastname: Hunter
mesh_terms: D001429:Bacteriochlorophylls / Q000096:biosynthesis*; D002734:Chlorophyll / Q000096:biosynthesis*; D002735:Chlorophyllides / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000378:metabolism*; D012242:Rhodobacter sphaeroides / Q000201:enzymology / Q000235:genetics; D046939:Synechocystis / Q000201:enzymology / Q000235:genetics
chemical_list: D001429:Bacteriochlorophylls; D002735:Chlorophyllides; D002734:Chlorophyll; D044925:Oxidoreductases Acting on CH-CH Group Donors