Summary for 5KK0
| Entry DOI | 10.2210/pdb5kk0/pdb |
| Related | 5KJA 5KJB 5KJD |
| Descriptor | Apocarotenoid-15,15'-oxygenase, FE (II) ION, CHLORIDE ION, ... (4 entities in total) |
| Functional Keywords | carotenoid cleavage dioxygenase, iron coordination, non-heme iron proteins, oxidoreductase |
| Biological source | Synechocystis sp. (strain PCC 6803 / Kazusa) |
| Total number of polymer chains | 4 |
| Total formula weight | 217550.96 |
| Authors | Sui, X.,Kiser, P.D.,Palczewski, K. (deposition date: 2016-06-20, release date: 2016-07-13, Last modification date: 2023-09-27) |
| Primary citation | Sui, X.,Golczak, M.,Zhang, J.,Kleinberg, K.A.,von Lintig, J.,Palczewski, K.,Kiser, P.D. Utilization of Dioxygen by Carotenoid Cleavage Oxygenases. J.Biol.Chem., 290:30212-30223, 2015 Cited by PubMed Abstract: Carotenoid cleavage oxygenases (CCOs) are non-heme, Fe(II)-dependent enzymes that participate in biologically important metabolic pathways involving carotenoids and apocarotenoids, including retinoids, stilbenes, and related compounds. CCOs typically catalyze the cleavage of non-aromatic double bonds by dioxygen (O2) to form aldehyde or ketone products. Expressed only in vertebrates, the RPE65 sub-group of CCOs catalyzes a non-canonical reaction consisting of concerted ester cleavage and trans-cis isomerization of all-trans-retinyl esters. It remains unclear whether the former group of CCOs functions as mono- or di-oxygenases. Additionally, a potential role for O2 in catalysis by the RPE65 group of CCOs has not been evaluated to date. Here, we investigated the pattern of oxygen incorporation into apocarotenoid products of Synechocystis apocarotenoid oxygenase. Reactions performed in the presence of (18)O-labeled water and (18)O2 revealed an unambiguous dioxygenase pattern of O2 incorporation into the reaction products. Substitution of Ala for Thr at position 136 of apocarotenoid oxygenase, a site predicted to govern the mono- versus dioxygenase tendency of CCOs, greatly reduced enzymatic activity without altering the dioxygenase labeling pattern. Reevaluation of the oxygen-labeling pattern of the resveratrol-cleaving CCO, NOV2, previously reported to be a monooxygenase, using a purified enzyme sample revealed that it too is a dioxygenase. We also demonstrated that bovine RPE65 is not dependent on O2 for its cleavage/isomerase activity. In conjunction with prior research, the results of this study resolve key issues regarding the utilization of O2 by CCOs and indicate that dioxygenase activity is a feature common among double bond-cleaving CCOs. PubMed: 26499794DOI: 10.1074/jbc.M115.696799 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.8 Å) |
Structure validation
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