title: Enzymatic formation of an unnatural hexacyclic C35 polyprenoid by bacterial squalene cyclase.
abstract: A C35 polyprene in which a farnesyl C15 unit is connected in a head-to-head fashion to a geranylgeranyl C20 unit was enzymatically converted to an unnatural hexacyclic polyprenoid by squalene:hopene cyclase from Alicyclobacillus acidocaldarius. This is the first demonstration of the remarkable ability of the squalene cyclizing enzyme to perform construction of unnatural hexacyclic skeleton. The cyclization of the C35 polyprene was initiated by a proton attack on the terminal double bond of the C15 unit and proceeded without rearrangement of carbon and hydrogen. The substrate should be folded in chair-chair-chair-chair-boat-boat conformation to achieve the stereochemistry of the cyclization product.
authors.affiliation: University of Shizuoka, School of Pharmaceutical Sciences, 52-1 Yada, Shizuoka 422-8526, Japan. abei@ys7.u-shizuoka-ken.ac.jp
authors.forename: Ikuro
authors.initials: I
authors.lastname: Abe
authors.forename: Hideya
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Noguchi
mesh_terms: D001407:Bacillus / Q000201:enzymology; D008190:Lyases / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism; D013729:Terpenes / Q000138:chemical synthesis*
chemical_list: D013729:Terpenes; D008190:Lyases; C022651:squalene cyclase