Crystal structures of substrate-free and retinoic acid-bound cyanobacterial cytochrome P450 CYP120A1.
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 A 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 triple-glycine 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 microM. 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 beta-ionone ring are modified by CYP120A1.
Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
Karin
K
Kühnel
Na
N
Ke
Max J
MJ
Cryle
Stephen G
SG
Sligar
Mary A
MA
Schuler
Ilme
I
Schlichting
D000077556:Alitretinoin; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism; D006900:Hydroxylation; D015474:Isotretinoin / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012172:Retinaldehyde / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D046939:Synechocystis / Q000201:enzymology*; D014212:Tretinoin / Q000737:chemistry* / Q000378:metabolism
D001426:Bacterial Proteins; D000077556:Alitretinoin; D014212:Tretinoin; D003577:Cytochrome P-450 Enzyme System; D015474:Isotretinoin; D012172:Retinaldehyde