title: An insect-specific P450 oxidative decarbonylase for cuticular hydrocarbon biosynthesis.
abstract: Insects use hydrocarbons as cuticular waterproofing agents and as contact pheromones. Although their biosynthesis from fatty acyl precursors is well established, the last step of hydrocarbon biosynthesis from long-chain fatty aldehydes has remained mysterious. We show here that insects use a P450 enzyme of the CYP4G family to oxidatively produce hydrocarbons from aldehydes. Oenocyte-directed RNAi knock-down of Drosophila CYP4G1 or NADPH-cytochrome P450 reductase results in flies deficient in cuticular hydrocarbons, highly susceptible to desiccation, and with reduced viability upon adult emergence. The heterologously expressed enzyme converts C(18)-trideuterated octadecanal to C(17)-trideuterated heptadecane, showing that the insect enzyme is an oxidative decarbonylase that catalyzes the cleavage of long-chain aldehydes to hydrocarbons with the release of carbon dioxide. This process is unlike cyanobacteria that use a nonheme diiron decarbonylase to make alkanes from aldehydes with the release of formate. The unique and highly conserved insect CYP4G enzymes are a key evolutionary innovation that allowed their colonization of land.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Qiu
authors.forename: Claus
authors.initials: C
authors.lastname: Tittiger
authors.forename: Claude
authors.initials: C
authors.lastname: Wicker-Thomas
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Le Goff
authors.forename: Sharon
authors.initials: S
authors.lastname: Young
authors.forename: Eric
authors.initials: E
authors.lastname: Wajnberg
authors.forename: Thierry
authors.initials: T
authors.lastname: Fricaux
authors.forename: Nathalie
authors.initials: N
authors.lastname: Taquet
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Blomquist
authors.forename: René
authors.initials: R
authors.lastname: Feyereisen
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D060105:Animal Shells / Q000737:chemistry*; D000818:Animals; D053898:Biosynthetic Pathways / Q000235:genetics / Q000502:physiology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004330:Drosophila / Q000737:chemistry / Q000201:enzymology*; D006838:Hydrocarbons / Q000378:metabolism*; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008861:Microsomes / Q000378:metabolism; D015394:Molecular Structure; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D034622:RNA Interference
chemical_list: D000447:Aldehydes; D006838:Hydrocarbons; D003577:Cytochrome P-450 Enzyme System; D009251:NADPH-Ferrihemoprotein Reductase