title: Role of the LolP cytochrome P450 monooxygenase in loline alkaloid biosynthesis.
abstract: The insecticidal loline alkaloids, produced by Neotyphodium uncinatum and related endophytes, are exo-1-aminopyrrolizidines with an ether bridge between C-2 and C-7. Loline alkaloids vary in methyl, acetyl, and formyl substituents on the 1-amine, which affect their biological activity. Enzymes for key loline biosynthesis steps are probably encoded by genes in the LOL cluster, which is duplicated in N. uncinatum, except for a large deletion in lolP2. The role of lolP1 was investigated by its replacement with a hygromycin B phosphotransferase gene. Compared to wild type N. uncinatum and an ectopic transformant, DeltalolP1 cultures had greatly elevated levels of N-methylloline (NML) and lacked N-formylloline (NFL). Complementation of DeltalolP1 with lolP1 under control of the Emericella nidulans trpC promoter restored NFL production. These results and the inferred sequence of LolP1 indicate that it is a cytochrome P450, catalyzing oxygenation of an N-methyl group in NML to the N-formyl group in NFL.
authors.affiliation: Department of Plant Pathology, University of Kentucky, 1405 Veterans Drive, Lexington, KY 40546-0312, USA.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Spiering
authors.forename: Jerome R
authors.initials: JR
authors.lastname: Faulkner
authors.forename: Dong-Xiu
authors.initials: DX
authors.lastname: Zhang
authors.forename: Caroline
authors.initials: C
authors.lastname: Machado
authors.forename: Robert B
authors.initials: RB
authors.lastname: Grossman
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Schardl
mesh_terms: D000470:Alkaloids / Q000096:biosynthesis* / Q000737:chemistry; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006999:Hypocreales / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D011523:Protoplasts / Q000378:metabolism
chemical_list: D000470:Alkaloids; D005656:Fungal Proteins; D003577:Cytochrome P-450 Enzyme System; C059478:loline