Identification of a gene required for cis-to-trans carotene isomerization in carotenogenesis of the cyanobacterium Synechocystis sp. PCC 6803

Plant Cell Physiol. 2001 Dec;42(12):1398-402. doi: 10.1093/pcp/pce167.


A disruptive mutant of the sll0033 gene of the cyanobacterium Synechocystis sp. PCC 6803 produced primarily cis carotenes and small amounts of all-trans carotenes, but no xanthophylls, under dark conditions. Under light conditions, however, it produced normal carotenoids, that were the same as those produced by wild-type cells grown under both light and dark conditions. When the mutant cells cultured under dark conditions were irradiated, cis-isomers of carotenes were converted to all-trans lycopene. These findings demonstrate that this gene, designated crtH, is involved in the isomerization of cis-carotenes to all-trans forms in dark conditions, and that cis-carotenes were also converted to all-trans forms under light conditions by photoisomerization.

Publication types

  • Comparative Study

MeSH terms

  • Antioxidants / metabolism
  • Carotenoids / chemistry
  • Carotenoids / isolation & purification
  • Carotenoids / metabolism*
  • Chromatography, High Pressure Liquid
  • Cyanobacteria / enzymology
  • Cyanobacteria / genetics*
  • Cyanobacteria / radiation effects
  • Darkness
  • Light
  • Lycopene
  • Mutation
  • Spectrum Analysis
  • Stereoisomerism
  • cis-trans-Isomerases / genetics*
  • cis-trans-Isomerases / metabolism


  • Antioxidants
  • Carotenoids
  • cis-trans-Isomerases
  • Lycopene