title: Expression and characterization of PP7, a novel plant protein Ser/Thr phosphatase distantly related to RdgC/PPEF and PP5.
abstract: We have recently identified an Arabidopsis thaliana cDNA encoding a putative protein Ser/Thr phosphatase PP7, not closely related to any protein phosphatases in animals or fungi. Here, we describe the characterization of PP7 expressed in a bacterial system. The recombinant protein was inactive unless the longest insert in its catalytic domain was cleaved, suggesting that this insert is an autoinhibitory region. PP7 was resistant to okadaic acid, calyculin and fumonisin B1, and was stimulated by Mn2+ or Fe2+, while Ni2+ and Zn2+ were inhibitory. Polylysine stimulated PP7 activity towards p-nitrophenylphosphate but inhibited activity towards the most efficient protein substrate, myelin basic protein. A tentative model of the control of PP7 activity is proposed.
authors.affiliation: Research School of Biological and Molecular Sciences, Oxford Brookes University, Headington, UK. p0071233@brookes.ac.uk
authors.forename: M A
authors.initials: MA
authors.lastname: Kutuzov
authors.forename: D E
authors.initials: DE
authors.lastname: Evans
authors.forename: A V
authors.initials: AV
authors.lastname: Andreeva
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins; D002264:Carboxylic Acids / Q000494:pharmacology; D002364:Caseins / Q000378:metabolism; D020134:Catalytic Domain; D002413:Cations, Divalent / Q000494:pharmacology; D029721:Drosophila Proteins; D004926:Escherichia coli / Q000235:genetics; D037341:Fumonisins; D006023:Glycoproteins / Q000235:genetics; D006493:Heparin / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D002479:Inclusion Bodies / Q000201:enzymology; D008387:Marine Toxins; D004676:Myelin Basic Protein / Q000378:metabolism; D009596:Nitrophenols / Q000378:metabolism; D019319:Okadaic Acid / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000378:metabolism; D010080:Oxazoles / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D011107:Polylysine / Q000378:metabolism / Q000494:pharmacology; D011257:Pregnancy Proteins / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins; D002264:Carboxylic Acids; D002364:Caseins; D002413:Cations, Divalent; D029721:Drosophila Proteins; D037341:Fumonisins; D006023:Glycoproteins; D008387:Marine Toxins; D004676:Myelin Basic Protein; D009596:Nitrophenols; D009943:Organophosphorus Compounds; D010080:Oxazoles; D011257:Pregnancy Proteins; D011993:Recombinant Fusion Proteins; C021240:tissue-factor-pathway inhibitor 2; D019319:Okadaic Acid; D011107:Polylysine; C008644:nitrophenylphosphate; C056933:fumonisin B1; C059041:calyculin A; D006493:Heparin; C491501:PP7 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases; C074643:rdgC protein, Drosophila