spheroidene monooxygenase and similar proteins
Spheroidene monooxygenase (such as Rhodobacter sphaeroides monooxygenase CrtA) catalyzes the asymmetrical introduction of one keto group at the C-2 position of spheroidene and two keto groups at the C-2 and C-2' positions of spirilloxanthin in carotenoid pathways. Spectroscopic analysis suggests CrtA may have a 5-coordinated heme at its active site and that it may be a novel oxygenase and not a P450 enzyme.
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