The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform

Minor J. Coon - One of the best experts on this subject based on the ideXlab platform.

  • REDUCTION OF ALKYL HYDROPEROXIDES TO ALCOHOLS: ROLE OF RUBREDOXIN, AN ELECTRON CARRIER IN THE BACTERIAL HYDROXYLATION OF HYDROCARBONS*
    2016
    Co-Authors: Rodney F. Bayer, Eglis T. Lode, Minor J. Coon
    Abstract:

    Summary: Alkyl hydroperoxides are reduced to alcohols in the presence of DPNH and homogeneous rubredoxin and rubredoxin-DPN reductase from Pseudomonas oleovorans. The reaction does not occur when TPNH is substituted for DPNH or when rubredoxins from anaerobic bacteria are substituted for the P. oleovorans Nonheme Iron Protein. The reaction appears to have broad substrate specificity; 1-octyl, 2-octyl, cyclohexyl, and cumyl hydroperoxides are all reduced at sig-nificant rates. The reduction of alkyl hydroperoxides is inhibited by cyanide, as is the hydroxylation of alkanes and fatty acids in the same enzyme system supplemented with the w-hydroxylase. Previous studies in this laboratory have shown that alkanes (1,2) and fatty acids (3,4) undergo hydroxylation in enzyme preparations of Pseudomonas oleovorans according to the equation: RCH3 f DPNH + H+ + 02+RCH20H + DPN+ + H20. The three enzymes found to be required in the overall reaction (5) were purified and identified as rubredoxin (6,7) rubredoxin-DPN reductase (a), and an o-hydroxylase (9). In the present paper evidence is presented that rubredoxin serves as an electron carrier in the reduction of alkyl hydroperoxides to the corresponding alcohols. Hydroperoxides were apparently first suggested as intermediates in micro-bial hydrocarbon oxidations by Imelik (10) in 1948, and numerous investigators have subsequently proposed a role for hydroperoxides or have studied their fat

  • Fatty acid omega-hydroxylase (alkane hydroxylase) from Pseudomonas oleovorans.
    Methods in Enzymology, 2004
    Co-Authors: Gary R. Griffith, Richard T. Ruettinger, Mckenna Ej, Minor J. Coon
    Abstract:

    Publisher Summary This chapter describes the purification procedure of fatty acid ω-hydroxylase (alkane hydroxylase) from Pseudomonas oleovorans. The hydroxylation system induced in Pseudomonas oleovorans by growth on alkanes contains three Proteins: NADH-rubredoxin reductase—a flavoProtein containing one molecule of flavin adenine dinucleotide (FAD) per polypeptide chain, rubredoxin—a red, Nonheme Iron Protein, and the ω-hydroxylase, which is an unusual example of a mono-oxygenase containing Nonheme Iron as the prosthetic group. Electron transfer in this system is as follows: NADH reductase → rubredoxin → ω-hydroxylase → O 2 . Ferredoxin-NADP reductase may be substituted for the bacterial reductase, provided that NADPH is used in place of NADH as the primary electron donor. The activity of the hydroxylase is determined as the octane-dependent rate of NADPH oxidation in a reaction mixture containing an excess of reductase and rubredoxin. In the chapter, the various steps are summarized in a table and are carried out at 4°.

Eckard Münck - One of the best experts on this subject based on the ideXlab platform.

  • Redesigning the blue copper azurin into a redox-active mononuclear Nonheme Iron Protein: Preparation and study of Fe(II)-M121E azurin
    Journal of the American Chemical Society, 2014
    Co-Authors: Jing Liu, Katlyn K. Meier, Shiliang Tian, Jun-long Zhang, Hongchao Guo, Charles E. Schulz, Howard Robinson, Mark J. Nilges, Eckard Münck
    Abstract:

    Much progress has been made in designing heme and dinuclear Nonheme Iron enzymes. In contrast, engineering mononuclear Nonheme Iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the Protein exhibits superoxide scavenging activity. Mossbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity.

M??nck Eckard - One of the best experts on this subject based on the ideXlab platform.

  • Redesigning the blue copper azurin into a redox-active mononuclear Nonheme Iron Protein: Preparation and study of Fe(II)-M121E azurin
    journal of the american chemical society, 2014
    Co-Authors: Liu Jing, Meier, Katlyn K., Tian Shiliang, Zhang Jun-long, Guo Hongchao, Schulz, Charles E., Robinson Howard, Nilges, Mark J., M??nck Eckard
    Abstract:

    Much progress has been made in designing heme and dinuclear Nonheme Iron enzymes. In contrast, engineering mononuclear Nonheme Iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the Protein exhibits superoxide scavenging activity. Mossbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity. ? 2014 American Chemical Society.SCI(E)EI03512337-1234413

Gary R. Griffith - One of the best experts on this subject based on the ideXlab platform.

  • Fatty acid omega-hydroxylase (alkane hydroxylase) from Pseudomonas oleovorans.
    Methods in Enzymology, 2004
    Co-Authors: Gary R. Griffith, Richard T. Ruettinger, Mckenna Ej, Minor J. Coon
    Abstract:

    Publisher Summary This chapter describes the purification procedure of fatty acid ω-hydroxylase (alkane hydroxylase) from Pseudomonas oleovorans. The hydroxylation system induced in Pseudomonas oleovorans by growth on alkanes contains three Proteins: NADH-rubredoxin reductase—a flavoProtein containing one molecule of flavin adenine dinucleotide (FAD) per polypeptide chain, rubredoxin—a red, Nonheme Iron Protein, and the ω-hydroxylase, which is an unusual example of a mono-oxygenase containing Nonheme Iron as the prosthetic group. Electron transfer in this system is as follows: NADH reductase → rubredoxin → ω-hydroxylase → O 2 . Ferredoxin-NADP reductase may be substituted for the bacterial reductase, provided that NADPH is used in place of NADH as the primary electron donor. The activity of the hydroxylase is determined as the octane-dependent rate of NADPH oxidation in a reaction mixture containing an excess of reductase and rubredoxin. In the chapter, the various steps are summarized in a table and are carried out at 4°.

Jing Liu - One of the best experts on this subject based on the ideXlab platform.

  • Redesigning the blue copper azurin into a redox-active mononuclear Nonheme Iron Protein: Preparation and study of Fe(II)-M121E azurin
    Journal of the American Chemical Society, 2014
    Co-Authors: Jing Liu, Katlyn K. Meier, Shiliang Tian, Jun-long Zhang, Hongchao Guo, Charles E. Schulz, Howard Robinson, Mark J. Nilges, Eckard Münck
    Abstract:

    Much progress has been made in designing heme and dinuclear Nonheme Iron enzymes. In contrast, engineering mononuclear Nonheme Iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the Protein exhibits superoxide scavenging activity. Mossbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity.

  • Redesigning the Blue Copper Azurin into a Redox-Active Mononuclear Nonheme Iron Protein: Preparation and Study of Fe(II)-M121E Azurin
    2014
    Co-Authors: Jing Liu, Shiliang Tian, Jun-long Zhang, Hongchao Guo, Charles E. Schulz, Howard Robinson, Mark J. Nilges, Katlyn K. Meier, Eckard Münck
    Abstract:

    Much progress has been made in designing heme and dinuclear Nonheme Iron enzymes. In contrast, engineering mononuclear Nonheme Iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe­(II)-M121E azurin (Az), by replacing the axial Met121 and Cu­(II) in wild-type azurin (wtAz) with Glu and Fe­(II), respectively. In contrast to the redox inactive Fe­(II)-wtAz, the Fe­(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the Protein exhibits superoxide scavenging activity. Mössbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe­(II)-M121EAz, Fe­(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe­(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity