A protein-serine phosphatase from the halophilic archaeon Haloferax volcanii.
We have detected a protein phosphatase activity in soluble extracts from the halophilic archaeon Haloferax volcanii. This activity was markedly stimulated by the divalent metal ions Mn2+ and Cd2+. It dephosphorylated phosphoseryl residues in casein, mixed histones, and phosphorylase a, but not phosphotyrosyl residues in reduced, carboxyamidomethylated and maleylated lysozyme. This protein phosphatase activity was inhibited by NaF, Zn2+, vanadate, molybdate, inorganic phosphate, inorganic pyrophosphate, or p-nitrophenyl phosphate, or by treatment with diethylpyrocarbonate. Activity was unaffected by other potential inhibitors or activators such as polyamines, heparin, cyclic nucleotides, Ca2+/calmodulin, tartrate, tetramisole, okadaic acid, microcystin LR, or sulfhydryl-modifying agents. The functional similarities between this protein-serine phosphatase and that previously identified in another archaeon, the extreme acidothermophile Sulfolobus solfataricus, suggest the existence of a family of divalent metal ion-stimulated protein-serine phosphatases of extremely ancient origin in the Archaea.
Department of Biochemistry and Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0308.
K A
KA
Oxenrider
P J
PJ
Kennelly
D002104:Cadmium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D004789:Enzyme Activation; D016931:Halobacteriales / Q000201:enzymology*; D008345:Manganese / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D013379:Substrate Specificity
D002413:Cations, Divalent; D010750:Phosphoproteins; D002104:Cadmium; D008345:Manganese; D010749:Phosphoprotein Phosphatases