Phytochrome from the green alga Mesotaenium caldariorum. Purification and preliminary characterization.

摘要: A method to purify the phytochrome photoreceptor from unicellular green alga Mesotaenium caldariorum is presented. Preparative scale formation of algal protoplasts and controlled osmotic cell lysis have permitted separation intact organelles phytochrome-enriched soluble protein fraction. We utilized observation that red light-absorbing (Pr) far-red (Pfr) forms are differentially retained on an anion exchange matrix M. apparent homogeneity. preparations with A650/A280 ratios greater than 0.78 exhibit a single 120-kDa band silver-stained sodium dodecyl sulfate-polyacrylamide gels. Immunoblot analyses using cross-reactive pea monoclonal antibody reveal 1) represents full-length polypeptide, 2) predominantly localized in cytoplasm, 3) there 150,000-250,000 molecules/cell. Steric exclusion high pressure liquid chromatography analysis under nondenaturing conditions indicates has mass 355 kDa. The absorption maxima for Pr Pfr 650 722 nm, respectively. Both blue-shifted compared those phytochromes dark-grown angiosperm tissue. molar coefficient at nm 86,800 +/- 2800 liter mol-1 cm-1, which lower higher plant phytochromes. significance similarities differences molecular properties sources discussed.