The Experts below are selected from a list of 414 Experts worldwide ranked by ideXlab platform

Bernard Witholt - One of the best experts on this subject based on the ideXlab platform.

  • cloning of baeyer villiger Monooxygenases from comamonas xanthobacter and rhodococcus using polymerase chain reaction with highly degenerate primers
    Environmental Microbiology, 2003
    Co-Authors: Jan B Van Beilen, Frederic Mourlane, Markus A Seeger, Jasminka Kovac, Zhi Li, Theo H M Smits, Urban Fritsche, Bernard Witholt
    Abstract:

    To clone novel type 1 Baeyer-Villiger Monooxygenase (BVMO) genes, we isolated or collected 25 bacterial strains able to grow on alicyclic compounds. Twelve of the bacterial strains yielded polymerase chain reaction (PCR) fragments with highly degenerate primers based on the sequences of known and putative BVMOs. All these fragments were found to encode peptides homologous to published BVMO sequences. The complete BVMO genes and flanking DNA were cloned from a Comamonas, a Xanthobacter and a Rhodococcus strain using the PCR fragments as probes. BVMO genes cloned from the first two strains could be expressed to high levels in Escherichia coli using standard expression vectors, and the recombinants converted cyclopentanone and cyclohexanone to the corresponding lactones. The Rhodococcus BVMO, a putative Steroid Monooxygenase, could be expressed after modification of the N-terminal sequence. However, recombinants expressing this protein did not show activity towards progesterone. An esterase homologue located directly upstream of the Xanthobacter BVMO gene and a dehydrogenase homologue encoded directly downstream of the Comamonas sp. NCIMB 9872 BVMO gene were also expressed in E. coli and shown to specify lactone hydrolase and cyclohexanol dehydrogenase activity respectively.

Dick B Janssen - One of the best experts on this subject based on the ideXlab platform.

  • 4 hydroxyacetophenone Monooxygenase from pseudomonas fluorescens acb a novel flavoprotein catalyzing baeyer villiger oxidation of aromatic compounds
    FEBS Journal, 2001
    Co-Authors: Nanne M Kamerbeek, Marco W. Fraaije, Maria Lle J H Moonen, Willem J H Van Berkel, Dick B Janssen
    Abstract:

    A novel flavoprotein that catalyses the NADPH-dependent oxidation of 4-hydroxyacetophenone to 4-hydroxyphenyl acetate, was purified to homogeneity from Pseudomonas fluorescens ACB. Characterization of the purified enzyme showed that 4-hydroxyacetophenone Monooxygenase (HAPMO) is a homodimer of approximate to 140 kDa with each subunit containing a noncovalently bound FAD molecule. HAPMO displays a tight coupling between NADPH oxidation and substrate oxygenation. Besides 4-hydroxyacetophenone a wide range of other acetophenones are readily converted via a Baeyer-Villiger rearrangement reaction into the corresponding phenyl acetates. The P. fluorescens HAPMO gene (hapE) was characterized. It encoded a 640 amino-acid protein with a deduced mass of 71 884 Da. Except for an N-terminal extension of approximate to 135 residues, the sequence of HAPMO shares significant similarity with two known types of Baeyer-Villiger Monooxygenases: cyclohexanone Monooxygenase (27-33% sequence identity) and Steroid Monooxygenase (33% sequence identity). The HAPMO sequence contains several sequence motifs indicative for the presence of two Rossman fold domains involved in FAD and NADPH binding. The functional role of a recently identified flavoprotein sequence motif (ATG) was explored by site-directed mutagenesis. Replacement of the strictly conserved glycine (G490) resulted in a dramatic effect on catalysis. From a kinetic analysis of the G490A mutant it is concluded that the observed sequence motif serves a structural function which is of importance for NADPH binding.

Jan B Van Beilen - One of the best experts on this subject based on the ideXlab platform.

  • cloning of baeyer villiger Monooxygenases from comamonas xanthobacter and rhodococcus using polymerase chain reaction with highly degenerate primers
    Environmental Microbiology, 2003
    Co-Authors: Jan B Van Beilen, Frederic Mourlane, Markus A Seeger, Jasminka Kovac, Zhi Li, Theo H M Smits, Urban Fritsche, Bernard Witholt
    Abstract:

    To clone novel type 1 Baeyer-Villiger Monooxygenase (BVMO) genes, we isolated or collected 25 bacterial strains able to grow on alicyclic compounds. Twelve of the bacterial strains yielded polymerase chain reaction (PCR) fragments with highly degenerate primers based on the sequences of known and putative BVMOs. All these fragments were found to encode peptides homologous to published BVMO sequences. The complete BVMO genes and flanking DNA were cloned from a Comamonas, a Xanthobacter and a Rhodococcus strain using the PCR fragments as probes. BVMO genes cloned from the first two strains could be expressed to high levels in Escherichia coli using standard expression vectors, and the recombinants converted cyclopentanone and cyclohexanone to the corresponding lactones. The Rhodococcus BVMO, a putative Steroid Monooxygenase, could be expressed after modification of the N-terminal sequence. However, recombinants expressing this protein did not show activity towards progesterone. An esterase homologue located directly upstream of the Xanthobacter BVMO gene and a dehydrogenase homologue encoded directly downstream of the Comamonas sp. NCIMB 9872 BVMO gene were also expressed in E. coli and shown to specify lactone hydrolase and cyclohexanol dehydrogenase activity respectively.

Jarosław J. Panek - One of the best experts on this subject based on the ideXlab platform.

  • Insight into the orientational versatility of Steroid substrates—a docking and molecular dynamics study of a Steroid receptor and Steroid Monooxygenase
    Journal of Molecular Modeling, 2017
    Co-Authors: Anna Panek, Alina Świzdor, Natalia Milecka-tronina, Jarosław J. Panek
    Abstract:

    Numerous Steroids are essential plant, animal, and human hormones. The medical and industrial applications of these hormones require the identification of new synthetic routes, including biotransformations. The metabolic fate of a Steroid can be complicated; it may be transformed into a variety of substituted derivatives. This may be because a Steroid molecule can adopt several possible orientations in the binding pocket of a receptor or an enzyme. The present study, based on docking and molecular dynamics, shows that it is indeed possible for a Steroid molecule to bind to a receptor binding site in two or more orientations (normal, head-to-tail reversed, upside down). Three Steroids were considered: progesterone, dehydroepiandrosterone, and 7-oxo-dehydroepiandrosterone. Two proteins were employed as hosts: the human mineralocorticoid receptor and a bacterial Baeyer–Villiger Monooxygenase. When the Steroids were in nonstandard orientations, the estimated binding strength was found to be only moderately diminished and the network of hydrogen bonds between the Steroid and the host was preserved.

  • Insight into the orientational versatility of Steroid substrates-a docking and molecular dynamics study of a Steroid receptor and Steroid Monooxygenase
    Journal of Molecular Modeling, 2017
    Co-Authors: Anna Panek, Alina Świzdor, Natalia Milecka-tronina, Jarosław J. Panek
    Abstract:

    Numerous Steroids are essential plant, animal, and human hormones. The medical and industrial applications of these hormones require the identification of new synthetic routes, including biotransformations. The metabolic fate of a Steroid can be complicated; it may be transformed into a variety of substituted derivatives. This may be because a Steroid molecule can adopt several possible orientations in the binding pocket of a receptor or an enzyme. The present study, based on docking and molecular dynamics, shows that it is indeed possible for a Steroid molecule to bind to a receptor binding site in two or more orientations (normal, head-to-tail reversed, upside down). Three Steroids were considered: progesterone, dehydroepiandrosterone, and 7-oxo-dehydroepiandrosterone. Two proteins were employed as hosts: the human mineralocorticoid receptor and a bacterial Baeyer–Villiger Monooxygenase. When the Steroids were in nonstandard orientations, the estimated binding strength was found to be only moderately diminished and the network of hydrogen bonds between the Steroid and the host was preserved.

Nanne M Kamerbeek - One of the best experts on this subject based on the ideXlab platform.

  • 4 hydroxyacetophenone Monooxygenase from pseudomonas fluorescens acb a novel flavoprotein catalyzing baeyer villiger oxidation of aromatic compounds
    FEBS Journal, 2001
    Co-Authors: Nanne M Kamerbeek, Marco W. Fraaije, Maria Lle J H Moonen, Willem J H Van Berkel, Dick B Janssen
    Abstract:

    A novel flavoprotein that catalyses the NADPH-dependent oxidation of 4-hydroxyacetophenone to 4-hydroxyphenyl acetate, was purified to homogeneity from Pseudomonas fluorescens ACB. Characterization of the purified enzyme showed that 4-hydroxyacetophenone Monooxygenase (HAPMO) is a homodimer of approximate to 140 kDa with each subunit containing a noncovalently bound FAD molecule. HAPMO displays a tight coupling between NADPH oxidation and substrate oxygenation. Besides 4-hydroxyacetophenone a wide range of other acetophenones are readily converted via a Baeyer-Villiger rearrangement reaction into the corresponding phenyl acetates. The P. fluorescens HAPMO gene (hapE) was characterized. It encoded a 640 amino-acid protein with a deduced mass of 71 884 Da. Except for an N-terminal extension of approximate to 135 residues, the sequence of HAPMO shares significant similarity with two known types of Baeyer-Villiger Monooxygenases: cyclohexanone Monooxygenase (27-33% sequence identity) and Steroid Monooxygenase (33% sequence identity). The HAPMO sequence contains several sequence motifs indicative for the presence of two Rossman fold domains involved in FAD and NADPH binding. The functional role of a recently identified flavoprotein sequence motif (ATG) was explored by site-directed mutagenesis. Replacement of the strictly conserved glycine (G490) resulted in a dramatic effect on catalysis. From a kinetic analysis of the G490A mutant it is concluded that the observed sequence motif serves a structural function which is of importance for NADPH binding.