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The sole cysteine residue (Cys301) of tetrathionate hydrolase from Acidithiobacillus ferrooxidans does not play a role in enzyme activity.
- Source :
-
Bioscience, biotechnology, and biochemistry [Biosci Biotechnol Biochem] 2014; Vol. 78 (12), pp. 2030-5. Date of Electronic Publication: 2014 Aug 21. - Publication Year :
- 2014
-
Abstract
- Cysteine residues are absolutely indispensable for the reactions of almost all enzymes involved in the dissimilatory oxidation pathways of reduced inorganic sulfur compounds. Tetrathionate hydrolase from the acidophilic iron- and sulfur-oxidizing bacterium Acidithiobacillus ferrooxidans (Af-Tth) catalyzes tetrathionate hydrolysis to generate elemental sulfur, thiosulfate, and sulfate. Af-Tth is a key enzyme in the dissimilatory sulfur oxidation pathway in this bacterium. Only one cysteine residue (Cys301) has been identified in the deduced amino acid sequence of the Af-Tth gene. In order to clarify the role of the sole cysteine residue, a site-specific mutant enzyme (C301A) was generated. No difference was observed in the retention volumes of the wild-type and mutant Af-Tth enzymes by gel-filtration column chromatography, and surprisingly the enzyme activities measured in the cysteine-deficient and wild-type enzymes were the same. These results suggest that the sole cysteine residue (Cys301) in Af-Tth is involved in neither the tetrathionate hydrolysis reaction nor the subunit assembly. Af-Tth may thus have a novel cysteine-independent reaction mechanism.
- Subjects :
- Acidithiobacillus genetics
Alanine chemistry
Alanine metabolism
Amino Acid Sequence
Bacterial Proteins chemistry
Bacterial Proteins metabolism
Cysteine chemistry
Enzyme Assays
Gene Expression
Hydrolases chemistry
Hydrolases metabolism
Hydrolysis
Kinetics
Molecular Sequence Data
Mutagenesis, Site-Directed
Oxidation-Reduction
Sequence Alignment
Acidithiobacillus enzymology
Bacterial Proteins genetics
Cysteine metabolism
Hydrolases genetics
Mutation
Subjects
Details
- Language :
- English
- ISSN :
- 1347-6947
- Volume :
- 78
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Bioscience, biotechnology, and biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 25144400
- Full Text :
- https://doi.org/10.1080/09168451.2014.948374