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Names | |
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Preferred IUPAC name 2-[(3S,4S,5S,6S,7E,9E,11E)-4,6-Dimethoxy-3,5,11-trimethyltrideca-7,9,11-trien-1-yl]-8-hydroxy-5,7-dimethoxy-3-methyl-4H-1-benzopyran-4-one | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider |
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ECHA InfoCard | 100.149.842 ![]() |
MeSH | Stigmatellin |
PubChem CID | |
CompTox Dashboard (EPA) | |
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Properties | |
C30H42O7 | |
Molar mass | 514.65 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Stigmatellin is a potent inhibitor of the quinol oxidation (Qo) site of the cytochrome bc1 complex in mitochondria[1] and the cytochrome b6f complex of thylakoid membranes. At higher concentrations, stigmatellin also inhibits Complex I, as a "Class B" inhibitor of that enzyme.[2]
Stigmatellin is isolated from the myxobacterium Stigmatella aurantica, and contains a 5,7-dimethoxy-8-hydroxychromone aromatic headgroup with a hydrophobic alkenyl chain in position 2. Crystal structures for stigmatellin-inhibited bc1 complex from bovine, avian, yeast (Saccharomyces cerevisiae) and bacterial (Rhodobacter capsulatus, Cereibacter sphaeroides, and Paracoccus denitrificans) sources are available. Stigmatellin binds at the cytochrome b Qo site in the '(heme) bl distal' position, and associates with the Rieske iron-sulfur protein via a hydrogen bond to histidine residue 181 (His-181), a ligand to the [2Fe2S] iron-sulfur cluster of this subunit. This association raises the midpoint potential of the iron-sulfur cluster from 290 to 540 mV and restricts movement of the cytoplasmic domain of the Rieske protein.