title: Purification of plant protein phosphatase PP7 and evidence for its redox regulation.
abstract: PP7, a recently identified protein Ser/Thr phosphatase of the PPP family distantly related to phosphatases PP5/PPT and PPEF/rdgC, was purified from cauliflower extracts to apparent homogeneity. Purified cauliflower PP7 and recombinant PP7 expressed in Escherichia coli exhibit light absorption in the visible range with a maximum at approximately 430 nm. Under nonreducing conditions, native PP7 exists as a mixture of monomer with an intramolecular disulfide bridge, disulfide-linked homodimer, and possibly disulfide-linked complexes with potential partner proteins. The activity of recombinant Arabidopsis thaliana PP7 is reversibly regulated by redox agents. The results demonstrate the existence of PP7 protein in planta and suggest a possibility of redox regulation of this protein phosphatase.
authors.affiliation: Research School of Biological and Molecular Sciences, Oxford Brookes University, Headington, Oxford, OX3 0BP, United Kingdom. aandreeva@brookes.ac.uk
authors.forename: A V
authors.initials: AV
authors.lastname: Andreeva
authors.forename: O V
authors.initials: OV
authors.lastname: Solov'eva
authors.forename: D L
authors.initials: DL
authors.lastname: Kakuev
authors.forename: M A
authors.initials: MA
authors.lastname: Kutuzov
mesh_terms: D017360:Arabidopsis / Q000201:enzymology; D029681:Arabidopsis Proteins; D001937:Brassica / Q000201:enzymology*; D004220:Disulfides; D015971:Gene Expression Regulation, Enzymologic; D010084:Oxidation-Reduction; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification* / Q000378:metabolism; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism; D020836:Protein Structure, Quaternary
chemical_list: D029681:Arabidopsis Proteins; D004220:Disulfides; D010940:Plant Proteins; C491501:PP7 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases