{
    "accession": "MITE0000426",
    "status": "active",
    "comment": "CitB is a cytochrome P450 monooxygenase that catalyzes the formation biaryl and aryl-oxygen-aryl ether bonds in the core tetrapeptide (YIYY)",
    "changelog": [
        {
            "version": "1",
            "date": "2026-07-03",
            "contributors": [
                "0009-0008-8086-5325"
            ],
            "reviewers": [
                "0000-0001-5701-0590"
            ],
            "comment": "New entry."
        }
    ],
    "enzyme": {
        "name": "CitB",
        "description": "Cytochrome P450",
        "references": [
            "doi:10.1021/acschembio.0c00430"
        ],
        "databaseIds": {
            "uniprot": "UPI0002F6195D",
            "genpept": "QLH55579.1",
            "mibig": "BGC0002043"
        },
        "cofactors": {
            "organic": [
                "Heme"
            ],
            "inorganic": [
                "Fe"
            ]
        }
    },
    "reactions": [
        {
            "tailoring": [
                "Biaryl bond formation",
                "Oxidation"
            ],
            "description": "CitB catalyzes the oxidative formation of C\u2013C and C\u2013O cross-links within the CitA precursor peptide and MxPep is responsible for maturation of the peptide by removing the leader sequence generating the intermediate product cittilin B.",
            "reactionSMARTS": "[#6:1]-[#6:2]-[#6@@:3](-[#6@@:5](/[#6:29](=[#8:30])-[#7:28]-[#6@:27](-[#6:31](-[#7:33]-[#6@@:34](-[#6:38]-[#6:39]1:[#6:44]:[#6:43]:[#6:42](-[#8]):[#6:41]:[#6:40]:1)\\[#6:35](-[#8:37])=[#8:36])=[#8:32])/[#6:26]-[#6:24]1:[#6:25]:[#6:19]:[#6:20](:[#6:22]:[#6:23]:1)-[#8:21])-[#7:6]-[#6:7](-[#6@:9](-[#6:11]-[#6:12]1:[#6:18]:[#6:17]:[#6:15](-[#8:16]):[#6:14]:[#6:13]:1)/[#7:10])=[#8:8])\\[#6:4]>>[#6:1]-[#6:2]-[#6@@:3](-[#6@:5]1/[#6:29](=[#8:30])-[#7:28]-[#6@@:27]2-[#6:31](-[#7:33]-[#6@@:34](-[#6:38]-[#6:39]3:[#6:40]:[#6:41]:[#6:42](-[#8]-[#6:22]4:[#6:23]:[#6:24](-[#6:26]/2):[#6:25]:[#6:19](:[#6:20]:4-[#8:21])-[#6:17]2:[#6:15](:[#6:14]:[#6:13]:[#6:12](:[#6:18]:2)-[#6:11]-[#6@:9](/[#7:10])-[#6:7](=[#8:8])-[#7:6]-1)-[#8:16]):[#6:43]:[#6:44]:3)\\[#6:35](-[#8:37])=[#8:36])=[#8:32])\\[#6:4]",
            "reactions": [
                {
                    "substrate": "CC[C@H](C)[C@H](NC(=O)[C@@H](N)Cc1ccc(O)cc1)C(=O)N[C@@H](Cc1ccc(O)cc1)C(=O)N[C@@H](Cc1ccc(O)cc1)C(=O)O",
                    "products": [
                        "CC[C@H](C)[C@@H]1NC(=O)[C@@H](N)Cc2ccc(O)c(c2)-c2cc3cc(c2O)Oc2ccc(cc2)C[C@@H](C(=O)O)NC(=O)[C@H](C3)NC1=O"
                    ],
                    "isIntermediate": true
                }
            ],
            "evidence": {
                "evidenceCode": [
                    "Heterologous expression",
                    "In vitro assay",
                    "Knock-out studies"
                ],
                "references": [
                    "doi:10.1021/acschembio.0c00430"
                ]
            }
        }
    ]
}