title: Novel Genes Encoding Hexadecanoic Acid Δ6-Desaturase Activity in a Rhodococcus sp.
abstract: cis-6-Hexadecenoic acid, a major component of human sebaceous lipids, is involved in the defense mechanism against Staphylococcus aureus infection in healthy skin and closely related to atopic dermatitis. Previously, Koike et al. (Biosci Biotechnol Biochem 64:1064-1066, 2000) reported that a mutant strain of Rhodococcus sp. produced cis-6-hexadecenoate derivatives from palmitate alkyl esters. From the mutant Rhodococcus strain, we identified and sequenced two open reading frames present in an amplified 5.7-kb region; these open reading frames encoded tandemly repeated Δ6-desaturase-like genes, Rdes1 and Rdes2. A phylogenetic tree indicated that Rdes1 and Rdes2 were different from previously known Δ6-desaturase genes, and that they formed a new cluster. Rdes1 and Rdes2 were each introduced into vectors and then expressed separately in Escherichia coli, and the fatty acid composition of the transformed cells was analyzed by gas chromatography and mass spectrometry. The amount of cis-6-hexadecenoic acid was significantly higher in Rdes1- or Rdes2-transformed E. coli cells (twofold and threefold, respectively) than in vector-only control cells. These results showed that cis-6-hexadecenoic acid was produced in E. coli cells by the rhodococcal Δ6-desaturase-like proteins.
authors.affiliation: Tochigi Research Laboratories of Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan. araki.hiroyuki@kao.co.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Araki
authors.affiliation: Tochigi Research Laboratories of Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hagihara
authors.affiliation: Tochigi Research Laboratories of Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Takigawa
authors.affiliation: Tochigi Research Laboratories of Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan.
authors.forename: Yukiharu
authors.initials: Y
authors.lastname: Tsujino
authors.affiliation: Tochigi Research Laboratories of Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Ozaki
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D050602:Linoleoyl-CoA Desaturase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010169:Palmitic Acids / Q000378:metabolism*; D010802:Phylogeny; D012240:Rhodococcus / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D010169:Palmitic Acids; C093821:hexadecenoic acid; D050602:Linoleoyl-CoA Desaturase