Purification and characterization of protein kinase CK2 from Candida albicans: evidence for the presence of two distinct regulatory subunits beta and beta'.
Protein kinase CK2 of Candida albicans has been purified to near homogeneity by a procedure which involves chromatography on DEAE-cellulose, phosphocellulose, Q-Sepharose, and heparin-agarose. The purified enzyme has the characteristic properties of animal and yeast CK2, i.e., it utilizes ATP as well as GTP as phosphate donor, phosphorylates serine and threonine residues on casein, is inhibited by low concentrations of heparin, and is stimulated by NaCl and polycationic compounds such as polylysine, spermine, and spermidine. The native form of the enzyme exhibits a molecular mass of 159 kDa, and SDS-PAGE analysis indicates that it is composed of four polypeptides with relative molecular masses of 44, 39, 37 and 36 kDa. The 39- and 37-kDa polypeptides were identified as distinct catalytic subunits alpha and alpha' on the basis of in situ phosphorylation assays and immunological recognition with heterologous antibodies. The purified kinase undergoes autophosphorylation on the 44- and 36-kDa polypeptides, a characteristic of the beta subunits from other species. Antibodies raised against the beta subunit of Drosophila melanogaster and human CK2 crossreact only with the 36-kDa polypeptide. The 44-kDa polypeptide was identified as an unusually large beta' subunit by Western blotting with an antibody raised against the beta' subunit of Saccharomyces cerevisiae. All these data suggest that C. albicans CK2 has an alpha alpha' beta beta' heterotetrameric composition similar to that found in S. cerevisiae.
Walz
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K
Cátedra de Microbiología, Facultad de Agronomía, CIBYF-CONICET, Universidad de Buenos Aires, Argentina.
Pardo
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Passeron
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D002176:Candida albicans / Q000201:enzymology*; D047390:Casein Kinase II; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification; D006493:Heparin / Q000494:pharmacology; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D010768:Phosphoserine / Q000737:chemistry; D010769:Phosphothreonine / Q000737:chemistry; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000302:isolation & purification*
D005656:Fungal Proteins; D007527:Isoenzymes; D046911:Macromolecular Substances; D010769:Phosphothreonine; D010768:Phosphoserine; D006493:Heparin; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases