title: A method for investigating the stereochemical course of terpene cyclisations.
abstract: Three sesquiterpene cyclases from Streptomyces scabei 87.22, Streptomyces venezuelae ATCC 10712 and Streptomyces clavuligerus ATCC 27064 were characterised and their products were identified as (-)-neomeranol B, (+)-isodauc-8-en-11-ol and (+)-intermedeol, respectively. The stereochemical courses of the terpene cyclisations were investigated by use of various (13)C-labelled FPP isotopomers. A quick and easy test was developed that allows to distinguish reprotonations of olefinic double bonds in neutral intermediates from the two stereoheterotopic faces. The method makes use of incubating (13)C-FPP isotopomers labelled at the reprotonated carbon in deuterium oxide and subsequent HSQC analysis of the product. A 1,7-cyclisation towards (+)-isodauc-8-en-11-ol was followed by use of (1,7-(13)C2)FPP. Surprisingly, the (+)-isodauc-8-en-11-ol also accepted (2Z,6E)-FPP resulting in the same product profile as obtained from (2E,6E)-FPP.
authors.affiliation: Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany. dickschat@uni-bonn.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Rabe
authors.affiliation: Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany. dickschat@uni-bonn.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Rinkel
authors.affiliation: Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany. dickschat@uni-bonn.de.
authors.forename: Tim A
authors.initials: TA
authors.lastname: Klapschinski
authors.affiliation: Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany. dickschat@uni-bonn.de.
authors.forename: Lena
authors.initials: L
authors.lastname: Barra
authors.affiliation: Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany. dickschat@uni-bonn.de.
authors.forename: Jeroen S
authors.initials: JS
authors.lastname: Dickschat
mesh_terms: D003500:Cyclization; D008968:Molecular Conformation; D013237:Stereoisomerism; D013729:Terpenes / Q000737:chemistry*
chemical_list: D013729:Terpenes