Partially Folded Structure of Flavin Adenine Dinucleotide-depleted Ferredoxin-NADP+ Reductase with Residual NADP+ Binding Domain

This research was originally published in the Journal of Biological Chemistry. Masahiro Maeda, Daizo Hamada, Masaru Hoshino, Yayoi Onda, Toshiharu Hase and Yuji Goto. Partially Folded Structure of Flavin Adenine Dinucleotide-depleted Ferredoxin-NADP+ Reductase with Residual NADP+ Binding Domain. J. Biol. Chem. 2002; 277, 17101-17107. © the American Society for Biochemistry and Molecular Biolog

On-site single pollen metabolomics reveals varietal differences in phosphatidylinositol synthesis under heat stress conditions in rice

Although a loss of healthy pollen grains induced by metabolic heat responses has been indicated to be a major cause of heat-induced spikelet sterility under global climate change, to date detailed information at pollen level has been lacking due to the technical limitations. In this study, we used picolitre pressure-probe-electrospray-ionization mass spectrometry (picoPPESI-MS) to directly determine the metabolites in heat-treated single mature pollen grains in two cultivars, heat-tolerant cultivar, N22 and heat-sensitive cultivar, Koshihikari. Heat-induced spikelet fertility in N22 and Koshihikari was 90.0% and 46.8%, respectively. While no treatment difference in in vitro pollen viability was observed in each cultivar, contrasting varietal differences in phosphatidylinositol (PI)(34:3) have been detected in mature pollen, together with other 106 metabolites. Greater PI content was detected in N22 pollen regardless of the treatment, but not for Koshihikari pollen. In contrast, there was little detection for phosphoinositide in the single mature pollen grains in both cultivars. Our findings indicate that picoPPESI-MS analysis can efficiently identify the metabolites in intact single pollen. Since PI is a precursor of phosphoinositide that induces multiple signaling for pollen germination and tube growth, the active synthesis of PI(34:3) prior to germination may be closely associated with sustaining spikelet fertility even at high temperatures.Fil: Wada, Hiroshi. Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization; JapónFil: Hatakeyama, Yuto. Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization; JapónFil: Nakashima, Taiken. Hokkaido University; JapónFil: Nonami, Hiroshi. Ehime University; JapónFil: Erra Balsells, Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Hakata, Makoto. Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization; JapónFil: Nakata, Keisuke. Ehime University; JapónFil: Hiraoka, Kenzo. University Of Yamanashi; JapónFil: Onda, Yayoi. Ehime University; JapónFil: Nakano, Hiroshi. Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization; Japó

Oxidative protein folding: Selective pressure for prolamin evolution in rice

During seed development, endosperm cells of highly productive cereals, including rice, synthesize disulfide-rich proteins in large amounts and deposit them into storage organelles. Disulfide bond formation involves electron transfer and generates H2O2 as a by-product. To ensure proper development and maturation of seeds, the endosperm cells must supply large amounts of oxidizing equivalents to dithiols in nascent proteins in a controlled manner. This review compares multiple oxidative protein folding systems in yeast, cultured human cells, and rice endosperm. We discuss possible roles of ERO1, other sulfhydryl oxidases, and the protein disulfide isomerase family in the formation of disulfide bonds in storage proteins and the development of protein bodies. Rice prolamins, encoded by a multigene family, are divided into Cys-rich and Cys-depleted subgroups. We discuss the potential importance of disulfide bond formation in the evolution of the prolamin family in japonica rice

Oxidative Protein-Folding Systems in Plant Cells

Plants are unique among eukaryotes in having evolved organelles: the protein storage vacuole, protein body, and chloroplast. Disulfide transfer pathways that function in the endoplasmic reticulum (ER) and chloroplasts of plants play critical roles in the development of protein storage organelles and the biogenesis of chloroplasts, respectively. Disulfide bond formation requires the cooperative function of disulfide-generating enzymes (e.g., ER oxidoreductase 1), which generate disulfide bonds de novo, and disulfide carrier proteins (e.g., protein disulfide isomerase), which transfer disulfides to substrates by means of thiol-disulfide exchange reactions. Selective molecular communication between disulfide-generating enzymes and disulfide carrier proteins, which reflects the molecular and structural diversity of disulfide carrier proteins, is key to the efficient transfer of disulfides to specific sets of substrates. This review focuses on recent advances in our understanding of the mechanisms and functions of the various disulfide transfer pathways involved in oxidative protein folding in the ER, chloroplasts, and mitochondria of plants

Distinct Roles of Protein Disulfide Isomerase and P5 Sulfhydryl Oxidoreductases in Multiple Pathways for Oxidation of Structurally Diverse Storage Proteins in Rice[W][OA]

This work examines the localization and functions of two protein disulfide isomerase family oxidoreductases in formation of protein storage bodies in rice endosperm, finding that the two have nonoverlapping localizations, activities, and biological functions