Dictyostelium discoideum protein phosphatase-1 catalytic subunit exhibits distinct biochemical properties
| Autor: | Wladia Viviani, Paulo A. Zaini, Luiz Paulo Andrioli, Aline Maria Da Silva |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Models
Molecular DNA Complementary Protein subunit Molecular Sequence Data Mutant macromolecular substances Biochemistry Dictyostelium discoideum chemistry.chemical_compound Catalytic Domain Protein Phosphatase 1 Phosphoprotein Phosphatases Animals Dictyostelium Amino Acid Sequence Molecular Biology Peptide sequence DNA Primers chemistry.chemical_classification Base Sequence Sequence Homology Amino Acid biology Protein phosphatase 1 Cell Biology biology.organism_classification Molecular biology Recombinant Proteins Enzyme chemistry Tautomycin Research Article Cysteine |
| Zdroj: | Biochemical Journal. 373:703-711 |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | Protein phosphatase-1 (PP1) is expressed ubiquitously and is involved in many eukaryotic cellular functions, although PP1 enzyme activity could not be detected in the social amoeba Dictyostelium discoideum cell extracts. In the present paper, we show that D. discoideum has a single copy gene that codes for the catalytic subunit of PP1 (DdPP1c). DdPP1c is expressed throughout the D. discoideum life cycle with constant levels of mRNA, and its protein and amino acid sequence show a mean identity of 80% with other PP1c enzymes. However, it has a distinctive difference: the substitution of a phenylalanine residue (Phe269 in the DdPP1c) for a highly conserved cysteine residue (Cys273 in rabbit PP1c) in a region that was shown to have a critical role in the interaction of rabbit PP1c with toxin inhibitors. Wild-type DdPP1c and an engineered mutant form in which Phe269 was replaced by a cysteine residue were expressed in Escherichia coli. Both recombinant activities were similarly inhibited by okadaic acid, tautomycin and microcystin. However, the Phe269→Cys mutation resulted in a large increase in enzyme activity towards phosphorylase a and a higher sensitivity to calyculin A. These results, together with the molecular modelling of DdPP1c structure, indicate that the Phe269 residue, which occurs naturally in D. discoideum, confers distinct biochemical properties on this enzyme. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|