title: Purification and Characterization of a Cryoprotective Protein (Cryoprotectin) from the Leaves of Cold-Acclimated Cabbage.
abstract: We have purified a protein (cryoprotectin) from the leaves of cold-acclimated cabbage (Brassica oleracea L.) that protects thylakoids from nonacclimated spinach (Spinacia oleracea L.) against freeze-thaw damage. The procedure involves precipitations by heat, ammonium sulfate, and the glycosaminoglycan heparin and column chromatography on Polyamide 6 and a C18 reverse-phase matrix. After reverse-phase chromatography we obtained a single band of an apparent molecular mass of 7 kD when fractions that showed cryoprotective activity were analyzed by sodium dodecyl sulfate gel electrophoresis and silver staining. Gel-filtration experiments confirmed that the active protein is a monomer of 7 kD native molecular mass. This 7-kD protein could be purified only from cold-acclimated cabbage, but not from plants grown under nonacclimating conditions. Using peroxidase-labeled lectins, we show that cryoprotectin is a glycoprotein and that the saccharide moiety contains [alpha]1-3-linked fucose.
authors.affiliation: Institut fur Pflanzenphysiologie und Mikrobiologie, Freie Universitat, Konigin Luise-Strasse 12-16, D-14195 Berlin, Germany (F.S., J.M.S., D.K.H.).
authors.forename: F.
authors.initials: F
authors.lastname: Sieg
authors.forename: W.
authors.initials: W
authors.lastname: Schroder
authors.forename: J. M.
authors.initials: JM
authors.lastname: Schmitt
authors.forename: D. K.
authors.initials: DK
authors.lastname: Hincha