Crystal structures of substrate-free and retinoic acid-bound cyanobacterial cytochrome P450 CYP120A1

Karin Kühnel, Na Ke, Max J. Cryle, Stephen G. Sligar, Mary A. Schuler, Ilme Schlichting

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27 Citations (Scopus)


The crystal structures of substrate-free and all-trans-retinoic acid-bound CYP120A1 from Synechocystis sp. PCC 6803 were determined at 2.4 and 2.1 Å resolution, respectively, representing the first structural characterization of a cyanobacterial P450. Features of CYP120A1 not observed in other P450 structures include an aromatic ladder flanking the channel leading to the active site and a tripleglycine motif within SRS5. Using spectroscopic methods, CYP120A1 is shown to bind 13-cis-retinoic acid, 9-cis-retinoic acid, and retinal with high affinity and dissociation constants of less than 1 μM. Metabolism of retinoic acid by CYP120A1 suggests that CYP120A1 hydroxylates a variety of retinoid derivatives in vivo. On the basis of the retinoic acid-bound CYP120A1 crystal structure, we propose that either carbon 2 or the methyl groups (C16 or C17) of the β-ionone ring are modified by CYP120A1.

Original languageEnglish
Pages (from-to)6552-6559
Number of pages8
Issue number25
Publication statusPublished - 24 Jun 2008
Externally publishedYes

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