Article · Wikipedia archive · Last revised Jun 30, 2026

Stigmatellin

Stigmatellin is a potent inhibitor of the quinol oxidation (Qo) site of the cytochrome bc1 complex in mitochondria and the cytochrome b6f complex of thylakoid membranes. At higher concentrations, stigmatellin also inhibits Complex I, as a "Class B" inhibitor of that enzyme.

Last revised
Jun 30, 2026
Read time
≈ 2 min
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Citations
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Stigmatellin
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Names
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
ECHA InfoCard 100.149.842
MeSH Stigmatellin
  • InChI=1S/C30H42O7/c1-10-18(2)13-11-12-14-22(33-6)21(5)29(36-9)19(3)15-16-23-20(4)27(31)26-24(34-7)17-25(35-8)28(32)30(26)37-23/h10-14,17,19,21-22,29,32H,15-16H2,1-9H3/b13-11+,14-12+,18-10+/t19-,21+,22-,29-/m0/s1 checkY
    Key: UZHDGDDPOPDJGM-CVOZLMQJSA-N checkY
  • InChI=1/C30H42O7/c1-10-18(2)13-11-12-14-22(33-6)21(5)29(36-9)19(3)15-16-23-20(4)27(31)26-24(34-7)17-25(35-8)28(32)30(26)37-23/h10-14,17,19,21-22,29,32H,15-16H2,1-9H3/b13-11+,14-12+,18-10+/t19-,21+,22-,29-/m0/s1
    Key: UZHDGDDPOPDJGM-CVOZLMQJBZ
  • O=C\1c2c(O/C(=C/1C)CC[C@H](C)[C@H](OC)[C@H](C)[C@@H](OC)\C=C\C=C\C(=C\C)C)c(O)c(OC)cc2OC
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).
☒N verify (what is checkY☒N ?)

Stigmatellin is a potent inhibitor of the quinol oxidation (Qo) site of the cytochrome bc1 complex in mitochondria1 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.

References

References

  1. von Jagow G, Ohnishi T (June 1985). "The chromone inhibitor stigmatellin--binding to the ubiquinol oxidation center at the C-side of the mitochondrial membrane". FEBS Letters. 185 (2): 311–5. Bibcode:1985FEBSL.185..311V. doi:10.1016/0014-5793(85)80929-7. PMID 2987042. S2CID 37956153.
  2. Fato R, Bergamini C, Bortolus M, Maniero AL, Leoni S, Ohnishi T, Lenaz G (May 2009). "Differential effects of mitochondrial Complex I inhibitors on production of reactive oxygen species". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1787 (5): 384–92. doi:10.1016/j.bbabio.2008.11.003. PMC 2724837. PMID 19059197.
Further reading

Further reading