title: Fusion-type lycopene beta-cyclase from a thermoacidophilic archaeon Sulfolobus solfataricus.
abstract: Examination of the sequence of a hypothetical gene with an unknown function included in the carotenogenic gene cluster in the genome of a thermoacidophilic archaeon Sulfolobus solfataricus led to the prediction that the gene encodes a novel-type lycopene beta-cyclase, whose N- and C-terminal halves are homologous to the subunits of the bacterial heterodimeric enzymes. The recombinant expression of the gene in lycopene-producing Escherichia coli resulted in the accumulation of beta-carotene in the cells, which verifies the function of the gene. Homologues of the archaeal lycopene beta-cyclase from various organisms such as bacteria, archaea, and fungi have been reported. Although their primary structures are clearly specific to the biological taxa, a phylogenetic analysis revealed the unexpected complicity of the evolutional route of these enzymes.
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aoba-yama 07, Sendai, Miyagi 980-8579, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hemmi
authors.forename: Satoru
authors.initials: S
authors.lastname: Ikejiri
authors.forename: Toru
authors.initials: T
authors.lastname: Nakayama
authors.forename: Tokuzo
authors.initials: T
authors.lastname: Nishino
mesh_terms: D001419:Bacteria / Q000201:enzymology; D002338:Carotenoids / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics; D019766:Genes, Archaeal; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D019753:Intramolecular Lyases / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D008956:Models, Chemical; D005810:Multigene Family; D010802:Phylogeny; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000378:metabolism; D016944:Sulfolobus / Q000201:enzymology*
chemical_list: D021122:Protein Subunits; D011994:Recombinant Proteins; D002338:Carotenoids; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase