Cytochrome P450-type Hydroxylation and Epoxidation in a Tyrosine-liganded Hemoprotein, Catalase-related Allene Oxide Synthase

Boeglin, William E.; Brash, Alan R.

doi:10.1074/jbc.m112.364216

Cited by 10 publications

(11 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The stereospecific epoxidation of 13 S -HOTE by Fg-cat matches the catalytic activity of the PhIO-activated P. homomalla cAOS with 8 R -HETE [9]. In the current work we also found that the 33-kD mini-catalase of Mycobacterium avium ssp.…”

Section: Discussionsupporting

confidence: 77%

“…(By contrast, the PhIO-activated P. homomalla cAOS with 8 R -HETE did not form any ketones [9]). The enzymatic oxidation of substrate hydroxyl to ketone and not involving dehydrogenases is the topic of several mechanistic studies (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Fresh 5 mM iodosylbenzene (PhIO) solution was prepared as described previously [9]. Into 3 mL 50 mM Tris pH 7.5 + 150 mM NaCl buffer containing 50 µM iodosylbenzene and 1 µM Fg-cat was added 50 µM 13 S -HOTE(ω3) or 13 S -HOTE(ω6) substrate and incubated for 15 min at room temperature.…”

Section: Methodsmentioning

confidence: 99%

“…In earlier work the catalase-related allene oxide synthase (cAOS) of the coral Plexaura homomalla was shown to have P450-like oxidative capabilities when activated with the oxygen donor iodosylbenzene [9]. Iodosylbenzene (PhIO) has long been employed in mechanistic studies of cytochromes P450 as it is a single oxygen donor that oxidizes the enzyme to Compound I and by-passes the need for molecular oxygen and the reducing equivalents from NADPH (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…refs [10–13]. When activated using PhIO, the P. homomalla cAOS catalyzed stereoselective epoxidations and hydroxylations of arachidonic acid and 8 R -hydroxy-eicosatetraenoic acid (the hydroxy analog of its natural 8R-hydroperoxy substrate) [9]. In the current work we further explored the oxidative capacity of catalase-related hemoproteins using three enzymes: Fg-cat, a 41 kD enzyme from Fusarium graminearum recently shown to act as a peroxidase using exclusively the 13 S -hydroperoxides of linoleic or α-linolenic acids [14]; a Pseudomonas fluorescens Pfl01 catalase (37.5 kD, accession number WP_011333788.1) with 32% sequence identity to Fg-cat; and the Mycobacterium avium ssp.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Oxidation of C18 Hydroxy‐Polyunsaturated Fatty Acids to Epoxide or Ketone by Catalase‐Related Hemoproteins Activated with Iodosylbenzene

Teder

Boeglin

Brash

2017

Lipids

Self Cite

View full text Add to dashboard Cite

Small catalase-related hemoproteins with a facility to react with fatty acid hydroperoxides were examined for their potential mono-oxygenase activity when activated using iodosylbenzene. The proteins tested were a Fusarium graminearum 41 kD catalase hemoprotein (Fg-cat, gene FGSG_02217), a Pseudomonas fluorescens Pfl01 catalase (37.5 kD, accession number WP_011333788.1), and a Mycobacterium avium ssp. paratuberculosis 33 kD catalase (gene MAP-2744c). 13-Hydroxy-octadecenoic acids (which are normally unreactive) were selected as substrates because these enyzmes react specifically with the corresponding 13S-hydroperoxides (Pakhomova et al, (2009) Protein Sci. 18:2559, and Teder et al, 2017, Biochim. Biophys. Acta, 1862:706). In the presence of iodosylbenzene Fg-cat converted 13S-hydroxy-fatty acids to two products: the 15,16-double bond of 13S-hydroxy α-linolenic acid was oxidized stereospecifically to the 15S,16R-cis-epoxide or the 13-hydroxyl was oxidized to the 13-ketone. Products were identified by UV, HPLC, LC-MS, NMR and by comparison with authentic standards prepared for this study. The Pfl01-cat displayed similar activity. MAP-2744c oxidized 13S-hydroxy-linoleic acid to the 13-ketone, and epoxidized the double bonds to form the 9,10-epoxy-13-hydroxy, 11,12-epoxy-13-hydroxy, and 9,10-epoxy-13-keto derivatives; equivalent transformations occurred with 9S-hydroxy-linoleic acid as substrate. In parallel incubations in the presence of iodosylbenzene, human catalase displayed no activity towards 13S-hydroxy-linoleic acid, as expected from the highly restricted access to its active site. The results indicted that with suitable transformation to Compound I, monooxygenase activity can be demonstrated by these catalase-related hemoproteins with tyrosine as the proximal heme ligand.

show abstract

Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Oxidation of C18 Hydroxy‐Polyunsaturated Fatty Acids to Epoxide or Ketone by Catalase‐Related Hemoproteins Activated with Iodosylbenzene

Teder

Boeglin

Brash

2017

Lipids

Self Cite

View full text Add to dashboard Cite

show abstract

The Thr–His Connection on the Distal Heme of Catalase‐Related Hemoproteins: A Hallmark of Reaction with Fatty Acid Hydroperoxides

2016

Self Cite

View full text Add to dashboard Cite

This review focuses on a group of heme peroxidases that retain the catalase fold in structure, yet show little or no reaction with hydrogen peroxide. Instead of a role in oxidative defense, generally these enzymes are involved in secondary metabolite biosynthesis. The prototypical enzyme is the catalase-related allene oxide synthase (cAOS), an enzyme that converts a specific fatty acid hydroperoxide to the corresponding allene oxide (epoxide). Other catalase-related enzymes form allylic epoxides, aldehydes or a bicyclobutane fatty acid. In all catalases, including these catalase relatives, a His residue on the distal face of the heme is absolutely required for activity. Its immediate neighbor in sequence as well as in three-dimensional space is conserved as Val in true catalases and changed to Thr in the fatty acid hydroperoxide-metabolizing enzymes. As explained herein, the Thr-His connection on the distal face of the heme is critical in switching the substrate specificity from H2O2 to the transformation of fatty acid hydroperoxide.

show abstract

Catalase-Related Allene Oxide Synthase, on a Biosynthetic Route to Fatty Acid Cyclopentenones: Expression and Assay of the Enzyme and Preparation of the 8 R -HPETE Substrate

Brash

2018

Marine Enzymes and Specialized Metabolism - Part B

Self Cite

View full text Add to dashboard Cite

Catalase-related allene oxide synthase (cAOS) is a hemoprotein that converts a specific fatty acid hydroperoxide to an unstable allene oxide intermediate at turnover rates in the order of 1000 per second. Fatty acid allene oxides are intermediates in the formation of cyclopentenone or hydrolytic products in marine systems, most notably the prostanoid-related clavulones. Although the key catalytic amino acid residues around the active site of cAOS are the same as in true catalases, cAOS does not react with hydrogen peroxide. cAOS occurs exclusively as the N-terminal domain of a naturally occurring fusion protein with a C-terminal lipoxygenase (LOX) domain that supplies the hydroperoxide substrate. In marine invertebrates, an 8R-LOX domain converts arachidonic acid to 8R-hydroperoxyeicosatetraenoic acid (8R-HPETE) and the cAOS domain forms an 8,9-epoxy allene oxide. The fusion protein from the sea whip octocoral Plexaura homomalla is the prototypical model with crystal structures of the individual domains. The cAOS (43kDa) expresses exceptionally well in Escherichia coli, with yields of up to 100mg/L. This article describes in detail expression and assay of the P. homomalla cAOS and two methods for the preparation of its 8R-HPETE substrate. Another article in this volume focuses on the P. homomalla 8R-LOX (Gilbert, Neau, & Newcomer, 2018).

show abstract

Cytochrome P450-type Hydroxylation and Epoxidation in a Tyrosine-liganded Hemoprotein, Catalase-related Allene Oxide Synthase

Cited by 10 publications

References 43 publications

Oxidation of C18 Hydroxy‐Polyunsaturated Fatty Acids to Epoxide or Ketone by Catalase‐Related Hemoproteins Activated with Iodosylbenzene

Oxidation of C18 Hydroxy‐Polyunsaturated Fatty Acids to Epoxide or Ketone by Catalase‐Related Hemoproteins Activated with Iodosylbenzene

The Thr–His Connection on the Distal Heme of Catalase‐Related Hemoproteins: A Hallmark of Reaction with Fatty Acid Hydroperoxides

Catalase-Related Allene Oxide Synthase, on a Biosynthetic Route to Fatty Acid Cyclopentenones: Expression and Assay of the Enzyme and Preparation of the 8 R -HPETE Substrate

Contact Info

Product

Resources

About