Catalytic residues and a predicted structure of tetrahydrobiopterin-dependent alkylglycerol mono-oxygenase
- Watschinger, Katrin Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
- Fuchs, Julian E. Institute of General, Inorganic and Theoretical Chemistry, Innrain 52a, Leopold Franzens University Innsbruck, A-6020 Innsbruck, Austria
- Yarov-Yarovoy, Vladimir Department of Physiology and Membrane Biology, School of Medicine, Room 4131, Tupper Hall, University of California, Davis, One Shields Avenue, Davis, CA 95616, U.S.A.
- Keller, Markus A. Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
- Golderer, Georg Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
- Hermetter, Albin Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
- Werner-Felmayer, Gabriele Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
- Hulo, Nicolas Swiss Institute for Bioinformatics, Centre Medical Universitaire, 1 rue Michel Servet, CH-1211 Geneva, Switzerland
- Werner, Ernst R. Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
- 2012-3-14
Published in:
- Biochemical Journal. - Portland Press Ltd.. - 2012, vol. 443, no. 1, p. 279-286
English
Alkylglycerol mono-oxygenase (EC 1.14.16.5) forms a third, distinct, class among tetrahydrobiopterin-dependent enzymes in addition to aromatic amino acid hydroxylases and nitric oxide synthases. Its protein sequence contains the fatty acid hydroxylase motif, a signature indicative of a di-iron centre, which contains eight conserved histidine residues. Membrane enzymes containing this motif, including alkylglycerol mono-oxygenase, are especially labile and so far have not been purified to homogeneity in active form. To obtain a first insight into structure–function relationships of this enzyme, we performed site-directed mutagenesis of 26 selected amino acid residues and expressed wild-type and mutant proteins containing a C-terminal Myc tag together with fatty aldehyde dehydrogenase in Chinese-hamster ovary cells. Among all of the acidic residues within the eight-histidine motif, only mutation of Glu137 to alanine led to an 18-fold increase in the Michaelis–Menten constant for tetrahydrobiopterin, suggesting a role in tetrahydrobiopterin interaction. A ninth additional histidine residue essential for activity was also identified. Nine membrane domains were predicted by four programs: ESKW, TMHMM, MEMSAT and Phobius. Prediction of a part of the structure using the Rosetta membrane ab initio method led to a plausible suggestion for a structure of the catalytic site of alkylglycerol mono-oxygenase.
- Language
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- English
- Open access status
- hybrid
- Identifiers
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- DOI 10.1042/BJ20111509
- ISSN 0264-6021
- Persistent URL
- https://sonar.ch/global/documents/190067
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