3DAN
Crystal Structure of Allene oxide synthase
Summary for 3DAN
| Entry DOI | 10.2210/pdb3dan/pdb |
| Related | 3DAM 3DBM |
| Descriptor | Cytochrome P450 74A2, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total) |
| Functional Keywords | aos heme cytochrome p450 structure, fatty acid biosynthesis, heme, iron, lipid synthesis, lyase, metal-binding, oxylipin biosynthesis |
| Biological source | Parthenium argentatum (Guayule rubber plant) |
| Cellular location | Note=Rubber particle: Q40778 |
| Total number of polymer chains | 1 |
| Total formula weight | 54149.47 |
| Authors | |
| Primary citation | Li, L.,Chang, Z.,Pan, Z.,Fu, Z.Q.,Wang, X. Modes of heme binding and substrate access for cytochrome P450 CYP74A revealed by crystal structures of allene oxide synthase. Proc.Natl.Acad.Sci.Usa, 105:13883-13888, 2008 Cited by PubMed Abstract: Cytochrome P450s exist ubiquitously in all organisms and are involved in many biological processes. Allene oxide synthase (AOS) is a P450 enzyme that plays a key role in the biosynthesis of oxylipin jasmonates, which are involved in signal and defense reactions in higher plants. The crystal structures of guayule (Parthenium argentatum) AOS (CYP74A2) and its complex with the substrate analog 13(S)-hydroxyoctadeca-9Z,11E-dienoic acid have been determined. The structures exhibit a classic P450 fold but possess a heme-binding mode with an unusually long heme binding loop and a unique I-helix. The structures also reveal two channels through which substrate and product may access and leave the active site. The entrances are defined by a loop between beta3-2 and beta3-3. Asn-276 in the substrate binding site may interact with the substrate's hydroperoxy group and play an important role in catalysis, and Lys-282 at the entrance may control substrate access and binding. These studies provide both structural insights into AOS and related P450s and a structural basis to understand the distinct reaction mechanism. PubMed: 18787124DOI: 10.1073/pnas.0804099105 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.8 Å) |
Structure validation
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