title: The influence of glycerol and chloroplast lipids on the spectral shifts of pigments associated with NADPH: protochlorophyllide oxidoreductase from Avena sativa L.
abstract: Dark-grown angiosperm seedlings lack chlorophylls, but accumulate protochlorophyllide a complexed with the light-dependent enzyme NADPH:protochlorophyllide oxidoreductase. Previous investigators correlated spectral heterogeneity of in vivo protochlorophyllide forms and a shift of chlorophyllide forms from 680 to 672 nm (Shibata shift) occurring after irradiation, with intact membrane structures which are destroyed by solubilization. We demonstrate here that the various protochlorophyllide forms and the Shibata shift which disappear upon solubilization are restored if the reconstituted complex is treated with plastid lipids and 80% (w/v) glycerol. We hypothesize that the lipids can form a cubic phase and that this is the precondition in vitro and in vivo for the observed spectral properties before and after irradiation.
authors.affiliation: Botanisches Institut der Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Klement
authors.forename: U
authors.initials: U
authors.lastname: Oster
authors.forename: W
authors.initials: W
authors.lastname: Rüdiger
mesh_terms: D018554:Avena / Q000201:enzymology / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D008027:Light; D050356:Lipid Metabolism; D010088:Oxidoreductases / Q000378:metabolism*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D011521:Protochlorophyllide / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
chemical_list: D011521:Protochlorophyllide; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase; D005990:Glycerol