title: Nitric oxide donor-mediated inhibition of phosphorylation shows that light-mediated degradation of photosystem II D1 protein and phosphorylation are not tightly linked.
abstract: An outcome of the photochemistry during oxygenic photosynthesis is the rapid turn over of the D1 protein in the light compared to the other proteins of the photosystem II (PS II) reaction center. D1 is a major factor of PS II instability and its replacement a primary event of the PS II repair cycle. D1 also undergoes redox-dependent phosphorylation prior to its degradation. Although it has been suggested that phosphorylation modulates D1 metabolism, reversible D1 phosphorylation was reported not to be essential for PS II repair in Arabidopsis. Thus, the involvement of phosphorylation in D1 degradation is controversial. We show here that nitric oxide donors inhibit in vivo phosphorylation of the D1 protein in Spirodela without inhibiting degradation of the protein. Thus, D1 phosphorylation is not tightly linked to D1 degradation in the intact plant.
authors.affiliation: Sustainable Agricultural Systems Laboratory, Building 001, Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705-2350, USA.
authors.forename: Isabelle S
authors.initials: IS
authors.lastname: Booij-James
authors.forename: Marvin
authors.initials: M
authors.lastname: Edelman
authors.forename: Autar K
authors.initials: AK
authors.lastname: Mattoo
mesh_terms: D001059:Apoproteins / Q000378:metabolism; D029064:Araceae / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D003545:Cysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D008027:Light; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D026403:S-Nitrosothiols / Q000494:pharmacology
chemical_list: D001059:Apoproteins; D020030:Nitric Oxide Donors; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D026403:S-Nitrosothiols; C002385:linsidomine; C021315:S-nitrosocysteine; D008981:Molsidomine; D003545:Cysteine