Catalytic Function of a Novel Protein Protochlorophyllide Oxidoreductase C of Arabidopsis thaliana

“…This mutant displayed no visible phenotype in white light, consistent with results of Frick et al (2003) using a similar PORB À mutant line. Light-adapted Arabidopsis plants express a third POR enzymes called PORC (Oosawa et al 2000;Su et al 2001;Pattanayak and Tripathy, 2002) that seems to functionally replace PORB in the knock-out line (Frick et al 2003). Western blot experiments confirmed that similar levels of the large and small subunits of ribulose-1,5-bisphosphate carboxylase/ oxygenase were present in chloroplasts of PORB À and wild-type plants (Fig.…”

Section: Resultsmentioning

confidence: 79%

In vitro-mutagenesis of NADPH:protochlorophyllide oxidoreductase B: two distinctive protochlorophyllide binding sites participate in enzyme catalysis and assembly

et al. 2006

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NADPH:protochlorophyllide oxidoreductase (POR) B is a key enzyme for the light-induced greening of etiolated angiosperm plants. It is nucleus-encoded, imported into the plastids posttranslationally, and assembled into larger light-harvesting POR:protochlorophyllide complexes termed LHPP (Reinbothe et al., Nature 397:80-84, 1999). An in vitro-mutagenesis approach was taken to study the role of the evolutionarily conserved Cys residues in pigment binding. Four Cys residues are present in the PORB of which two, Cys276 and Cys303, established distinct pigment binding sites, as shown by biochemical tests, protein import studies, and in vitro-reconstitution experiments. While Cys276 constituted the Pchlide binding site in the active site of the enzyme, Cys303 established a second, low affinity pigment binding site that was involved in the assembly and stabilization of imported PORB enzyme inside etioplasts.

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“…The methods of expressing and purifying of C. bungeana hexahistidine-tagged-PORB in coli Rosetta TM (DE3) cells were described previously (Pattanayak and Tripathy 2002). The purified hexahistidine-tagged-PORB protein was injected subcutaneously into rabbits to produce antibody for following western blot experiments.…”

Section: Antibody Preparation and Western Blotmentioning

confidence: 99%

Influence of low temperatures on photosystem II photochemistry and expression of the NADPH:protochlorophyllide oxidoreductase in the alpine, subnival perennial, Chorispora bungeana

Li¹,

Sun²,

Xu³

et al. 2010

Photosynt.

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Low temperature significantly influences chloroplast development and chlorophyll (Chl) biosynthesis, so effect of coldness on Chl content and Chl fluorescence characteristics was investigated in C. bungeana (Chorispora bungeana Fisch. & C.A. Mey). The levels of transcript and protein of an enzymatic step during Chl biosynthesis in response to chilling (4°C) and freezing (−4°C) were also examined in this work. Significant reduction in total Chl content was observed, but the reduction was much less at 4°C than that at −4°C. Moreover, the maximal quantum efficiency of photosystem II (PSII) photochemistry, indicated by F v /F m , decreased in the first 12 h, but then started to increase and reached higher levels than the control at 24 h and 48 h at 4°C, but decreased continuously at −4°C. Whereas quantum yield of PSII (Φ PSII ) showed no significant difference between the chilling-stressed and the control seedlings, at −4°C, Φ PSII was markedly reduced with the prolonged treatment. In general, there were no significant responses of photochemical quenching (q P ) and non-photochemical quenching (NPQ) to cold treatment. Meanwhile, the full-length cDNA of NADPH:protochlorophyllide oxidoreductase (POR, EC 1.3.1.33) was isolated and termed CbPORB (GenBank Accession No. FJ390503). Its transcript and protein content only slightly declined at 4°C, but dramatically reduced at −4°C with the time. These results strongly suggest that CbPORB possesses certain resistant characteristics and is a major player in Chl biosynthesis process involved in plant growth and development of C. bungeana under cold environmental conditions.

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Catalytic Function of a Novel Protein Protochlorophyllide Oxidoreductase C of Arabidopsis thaliana

Cited by 37 publications

References 26 publications

Photoprotective role of NADPH:protochlorophyllide oxidoreductase A

Photoprotective role of NADPH:protochlorophyllide oxidoreductase A

In vitro-mutagenesis of NADPH:protochlorophyllide oxidoreductase B: two distinctive protochlorophyllide binding sites participate in enzyme catalysis and assembly

Influence of low temperatures on photosystem II photochemistry and expression of the NADPH:protochlorophyllide oxidoreductase in the alpine, subnival perennial, Chorispora bungeana

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