80054-40-6Relevant articles and documents
Stereochemistry of an alcohol oxidase from the defensive secretion of larvae of the leaf beetle Phaedon armoraciae (Coleoptera: Chrysomelidae)
Veith, Martin,Dettner, Konrad,Boland, Wilhelm
, p. 6601 - 6612 (1996)
Larvae of the leaf beetle Phaedon armoraciae produce the iridoids chrysomelidial 1 and plagiodial 3 from geraniol 6 by an oxidative sequence identical to that known in plants. Following ω-oxidation of geraniol the resulting 8-hydroxygeraniol 7 is oxidised via 8-oxogeraniol 14 and 8-hydroxygeranial 15 and to the dialdehyde 8. In plants this transformation is achieved by NADP+ dependent oxidoreductases. However, in the defensive secretion of several leaf beetles an oxygen-dependent oxidase is present. The enzyme catalyses the removal of the C(1)- and C(8)-H(R) hydrogen atoms (Re-specificity) from the diol 7 yielding 8-oxogeranial 8.
Structures of Iridoid Synthase from Cantharanthus roseus with Bound NAD+, NADPH, or NAD+/10-Oxogeranial: Reaction Mechanisms
Hu, Yumei,Liu, Weidong,Malwal, Satish R.,Zheng, Yingying,Feng, Xinxin,Ko, Tzu-Ping,Chen, Chun-Chi,Xu, Zhongxia,Liu, Meixia,Han, Xu,Gao, Jian,Oldfield, Eric,Guo, Rey-Ting
, p. 15478 - 15482 (2015)
Structures of the iridoid synthase nepetalactol synthase in the presence of NAD+, NADPH or NAD+/10-oxogeranial were solved. The 10-oxogeranial substrate binds in a transoid-O1-C3 conformation and can be reduced by hydride addition to form the byproduct S-10-oxo-citronellal. Tyr178 Oζ is positioned 2.5 ? from the substrate O1 and provides the second proton required for reaction. Nepetalactol product formation requires rotation about C1-C2 to form the cisoid isomer, leading to formation of the cis-enolate, together with rotation about C4-C5, which enables cyclization and lactol production. The structure is similar to that of progesterone-5β-reductase, with almost identical positioning of NADP, Lys146(147), Tyr178(179), and F342(343), but only Tyr178 and Phe342 appear to be essential for activity. The transoid 10-oxogeranial structure also serves as a model for β-face hydride attack in progesterone 5β-reductases and is of general interest in the context of asymmetric synthesis.
The aphid sex pheromone cyclopentanoids: Synthesis in the elucidation of structure and biosynthetic pathways
Dawson, Glenn W.,Pickett, John A.,Smiley, Diane W. M.
, p. 351 - 361 (2007/10/03)
Identification of a range of aphid sex pheromones as comprising the cyclopentanoids (4aS,7S,7aR)-nepetalactone, (1R,4aS,7S,7aR)-nepetalactol and the (1S)- and (1R,4aR,7S,7aS)-nepetalactols required samples authenticated by 1H and 13C NMR. These and related compounds were provided by small scale synthesis and extraction from plants in the genus Nepeta (Lamiaceae). The subsequent discovery that the synthetic sex pheromones could attract males, and also parasitic wasps that attack aphids, has created a need for large scale syntheses of the cyclopentanoids. This is afforded by cyclisation of the 8-oxo-1-enamine of citronellal as originally developed by Schreiber and co-workers (1986). Investigation into the biosynthesis of the cyclopentanoids by plants for exploiting aphid sex pheromones in crop protection by means of molecular biology required synthesis of putative biosynthetic intermediates, some with radioactive isotopic labelling, particularly 8-oxidised monoterpene alcohols and aldehydes.
