The Three-Dimensional Structure of an Arachidonic Acid 15-Lipoxygenase
| Autor: | L.M. Amzel, J C Boyington, Betty J. Gaffney |
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| Rok vydání: | 1993 |
| Předmět: |
Models
Molecular chemistry.chemical_classification Multidisciplinary biology Protein Conformation Stereochemistry Iron Molecular Sequence Data Substrate (chemistry) Ligands Lipoxygenase Beta barrel Protein structure chemistry Oxidoreductase biology.protein Arachidonate 15-Lipoxygenase Amino Acid Sequence Soybeans Peptide sequence Protein secondary structure Coordination geometry |
| Zdroj: | Science. 260:1482-1486 |
| ISSN: | 1095-9203 0036-8075 |
| DOI: | 10.1126/science.8502991 |
| Popis: | In mammals, the hydroperoxidation of arachidonic acid by lipoxygenases leads to the formation of leukotrienes and lipoxins, compounds that mediate inflammatory responses. Lipoxygenases are dioxygenases that contain a nonheme iron and are present in many animal cells. Soybean lipoxygenase-1 is a single-chain, 839-residue protein closely related to mammalian lipoxygenases. The structure of soybean lipoxygenase-1 solved to 2.6 angstrom resolution shows that the enzyme has two domains: a 146-residue beta barrel and a 693-residue helical bundle. The iron atom is in the center of the larger domain and is coordinated by three histidines and the COO- of the carboxyl terminus. The coordination geometry is nonregular and appears to be a distorted octahedron in which two adjacent positions are not occupied by ligands. Two cavities, in the shapes of a bent cylinder and a frustum, connect the unoccupied positions to the surface of the enzyme. The iron, with two adjacent and unoccupied positions, is poised to interact with the 1,4-diene system of the substrate and with molecular oxygen during catalysis. |
| Databáze: | OpenAIRE |
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