Epoxyalcohol synthase of Ectocarpus siliculosus. First CYP74-related enzyme of oxylipin biosynthesis in brown algae.
Biochim Biophys Acta Mol Cell Biol Lipids
; 1862(2): 167-175, 2017 Feb.
Article
in En
| MEDLINE
| ID: mdl-27863255
ABSTRACT
Enzymes of CYP74 family play the central role in the biosynthesis of physiologically important oxylipins in land plants. Although a broad diversity of oxylipins is known in the algae, no CYP74s or related enzymes have been detected in brown algae yet. Cloning of the first CYP74-related gene CYP5164B1 of brown alga Ectocarpus siliculosus is reported in present work. The recombinant protein was incubated with several fatty acid hydroperoxides. Linoleic acid 9-hydroperoxide (9-HPOD) was the preferred substrate, while linoleate 13-hydroperoxide (13-HPOD) was less efficient. α-Linolenic acid 9- and 13-hydroperoxides, as well as eicosapentaenoic acid 15-hydroperoxide were inefficient substrates. Both 9-HPOD and 13-HPOD were converted into epoxyalcohols. For instance, 9-HPOD was turned primarily into (9S,10S,11S,12Z)-9,10-epoxy-11-hydroxy-12-octadecenoic acid. Both epoxide and hydroxyl oxygen atoms of the epoxyalcohol were incorporated mostly from [18O2]9-HPOD. Thus, the enzyme exhibits the activity of epoxyalcohol synthase (EsEAS). The results show that the EsEAS isomerizes the hydroperoxides into epoxyalcohols via epoxyallylic radical, a common intermediate of different CYP74s and related enzymes. EsEAS can be considered as an archaic prototype of CYP74 family enzymes.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Plant Proteins
/
Cytochrome P-450 Enzyme System
/
Phaeophyceae
/
Epoxy Compounds
/
Oxylipins
Language:
En
Journal:
Biochim Biophys Acta Mol Cell Biol Lipids
Year:
2017
Type:
Article
Affiliation country:
RUSSIA