Functional Characterization of an Extremely Thermophilic ATPase in Membranes of the Crenarchaeon Acidianus ambivalens
-
Michael Hinrichs
Abstract
A plasma membrane-bound adenosine triphosphatase with specific activities up to 0.2 μmol min−1 (mg protein)−1 at 80°C was detected in the thermoacidophilic crenarchaeon Acidianus ambivalens (DSM 3772). The enzymatic activity exhibited a broad pH-optimum in the neutral range with two suboptima at pH 5.5 and 7.0, respectively. Sulfite activation resulted in only one pH optimum at 6.25. In the presence of the divalent cations Mg2+ and Mn2+ the ATPase activity was maximal. Remarkably, the hydrolytic rates of GTP and ITP were substantially higher than for ATP. ADP and pyrophosphate were only hydrolyzed with small rates, whereas AMP was not hydrolyzed at all. Both activities could be weakly inhibited by the classical F-type ATPase inhibitor N, N′dicyclohexylcarbodiimide, whereas azide had no influence at all. The classical inhibitor of V-type ATPases, nitrate, also exerted a small inhibitory effect. The strongly specific V-type ATPase inhibitor concanamycin A, however, showed no effect at all. The P-type ATPase inhibitor vanadate had no inhibitory effect on the ATPase activity at pH 7.0, whereas a remarkable inhibition at high concentrations could be observed for the activity at pH 5.5. Arrhenius plots for both membrane bound ATPase activities were linear up to 95°C, reflecting the enormous thermostability of the enzyme.
Copyright (c) 1999 by Walter de Gruyter GmbH & Co. KG
Articles in the same Issue
- Execution of Apoptosis: Converging or Diverging Pathways?
- Two Highly Related Homeodomain Proteins, Nkx5-1 and Nkx5-2, Display Different DNA Binding Specificities
- The Janus Face of the Archaeal Cdc48/p97 Homologue VAT: Protein Folding versus Unfolding
- Functional Characterization of an Extremely Thermophilic ATPase in Membranes of the Crenarchaeon Acidianus ambivalens
- On the Lysosomal Degradation of Neurofibromin and Its Phosphorylation in Cultured Melanocytes
- Rat Muscle Fructose-1,6-Bisphosphatase: Cloning of the cDNA, Expression of the Recombinant Enzyme, and Expression Analysis in Different Tissues
- Catalase-Peroxidase from the Cyanobacterium Synechocystis PCC 6803: Cloning, Overexpression in Escherichia coli, and Kinetic Characterization
- Expression of Plasma Prekallikrein mRNA in Human Nonhepatic Tissues and Cell Lineages Suggests Special Local Functions of the Enzyme
- Biochemical Characterization of the Catalytic Domain of Membrane-Type 4 Matrix Metalloproteinase
- Fluorometric Microassays for the Determination of Cathepsin L and Cathepsin S Activities in Tissue Extracts
- The Role of Protein Phosphatase 2A Catalytic Subunit Cα in Embryogenesis: Evidence from Sequence Analysis and Localization Studies
- DNA Binding of Myc/Max/Mad Network Complexes to Oligonucleotides Containing Two E Box Elements: c-Myc/Max Heterodimers Do Not Bind DNA Cooperatively
- Tight Interaction between Densely Methylated DNA Fragments and the Methyl-CpG Binding Domain of the Rat MeCP2 Protein Attached to a Solid Support
- Molecular Characterization of a Novel Mammalian DnaJ-Like Sec63p Homolog
Articles in the same Issue
- Execution of Apoptosis: Converging or Diverging Pathways?
- Two Highly Related Homeodomain Proteins, Nkx5-1 and Nkx5-2, Display Different DNA Binding Specificities
- The Janus Face of the Archaeal Cdc48/p97 Homologue VAT: Protein Folding versus Unfolding
- Functional Characterization of an Extremely Thermophilic ATPase in Membranes of the Crenarchaeon Acidianus ambivalens
- On the Lysosomal Degradation of Neurofibromin and Its Phosphorylation in Cultured Melanocytes
- Rat Muscle Fructose-1,6-Bisphosphatase: Cloning of the cDNA, Expression of the Recombinant Enzyme, and Expression Analysis in Different Tissues
- Catalase-Peroxidase from the Cyanobacterium Synechocystis PCC 6803: Cloning, Overexpression in Escherichia coli, and Kinetic Characterization
- Expression of Plasma Prekallikrein mRNA in Human Nonhepatic Tissues and Cell Lineages Suggests Special Local Functions of the Enzyme
- Biochemical Characterization of the Catalytic Domain of Membrane-Type 4 Matrix Metalloproteinase
- Fluorometric Microassays for the Determination of Cathepsin L and Cathepsin S Activities in Tissue Extracts
- The Role of Protein Phosphatase 2A Catalytic Subunit Cα in Embryogenesis: Evidence from Sequence Analysis and Localization Studies
- DNA Binding of Myc/Max/Mad Network Complexes to Oligonucleotides Containing Two E Box Elements: c-Myc/Max Heterodimers Do Not Bind DNA Cooperatively
- Tight Interaction between Densely Methylated DNA Fragments and the Methyl-CpG Binding Domain of the Rat MeCP2 Protein Attached to a Solid Support
- Molecular Characterization of a Novel Mammalian DnaJ-Like Sec63p Homolog
