申请人:Iowa State University Research Foundation, Inc.
公开号:US07833748B1
公开(公告)日:2010-11-16
The present invention relates to the isolation, purification, sequencing, and functional characterization of the class I diterpene synthase sequence OsKSL11. Transcriptional control of OsKSL11 provides a means of regulating production of stemodene. Further, since OsKSL11 is highly homologous to OsKSL8, identification of the sequence of OsKSL11 will facilitate identification of underlying enzymatic determinants that affect product outcomes with these enzymes.
Biosynthesis of Cyclic Diterpene Hydrocarbons in Rice Cell Suspensions: Conversion of 9,10-syn-Labda-8(17),13-dienyl Diphosphate to 9β-Pimara-7,15-diene and Stemar-13-ene
作者:Ram S. Mohan、Nathan K.N. Yee、Robert M. Coates、Yue-Ying Ren、Predrag Stamenkovic、Irena Mendez、Charles A. West
DOI:10.1006/abbi.1996.0223
日期:1996.6
stemar-13-ene (10) were identified as majorproducts by comparisons with authentic standards. Marked increases in diterpene synthase activities were observed with enzyme from chitin-treated cells: (E,E,E)-GGPP (approximately 100 fold), ent-CPP (approximately 3 fold), and syn-CPP (approximately 60 fold). The very low conversions of (E,Z,E)-GGPP to hydrocarbon products excludes its role in the biosynthesis of
Diastereoselective Total Synthesis of (+)-13-Stemarene by Fourth Generation Methods: A Formal Total Synthesis of (+)-18-Deoxystemarin
作者:Francesca Leonelli、Federico Blesi、Paolo Dirito、Andrea Trombetta、Francesca Ceccacci、Angela La Bella、Luisa M. Migneco、Rinaldo Marini Bettolo
DOI:10.1021/jo200945s
日期:2011.8.19
The problem of constructing diastereoselectively the C/D ring system of stemarane diterpenes from a bicyclo[2.2.2]octane intermediate was solved resulting in very simple synthesis of (+)-13-stemarene 1. The obtaining of the latter represents also a formal synthesis of (+)-18-deoxystemarin 2. In the key step, the epimeric mixture 10, dissolved in toluene, was converted by the action of TsOH into (+)-stemar-13-en-15-one 28.
Stemar-13-ene synthase, a diterpene cyclase involved in the biosynthesis of the phytoalexin oryzalexin S in rice
In suspension‐cultured rice cells, diterpenoid phytoalexins are produced in response to exogenously applied elicitors. We isolated a cDNA encoding a diterpene cyclase, OsDTC2, from suspension‐cultured rice cells treated with a chitin elicitor. The OsDTC2 cDNA was overexpressed in Escherichia coli as a fusion protein with glutathione S‐transferase, and the recombinant OsDTC2 was indicated to function as stemar‐13‐ene synthase that converted syn‐copalyl diphosphate to stemar‐13‐ene, a putative diterpene hydrocarbon precursor of the phytoalexin oryzalexin S. The level of OsDTC2 mRNA in suspension‐cultured rice cells began to increase 3 h after addition of the elicitor and reached the maximum after 8 h. The expression of OsDTC2 was also induced in UV‐irradiated rice leaves. In addition, we indicated that stemar‐13‐ene accumulated in the chitin‐elicited suspension‐cultured rice cells and the UV‐irradiated rice leaves.
Studies for a Diastereoselective Synthesis of the Tetracyclic Diterpenic Diol Stemarin: A Model Study for a New Preparation of the Key Intermediate and the Synthesis of (+)-18-Deoxystemarin
Methods for a stereoselective preparation of compounds of type 2b, a keyintermediate of a previous synthesis of the tetracyclic diterpene stemarin (la), have been tested on model compounds 5a, 5c, and 8a. Thus, (±)-(1RS,6SR,8SR,11SR)-hydroxytricyclo[6.2.2.0l,6]dodecan-9-one (5a) was transformed by the Mitsunobu reaction into (±)-(1RS,6SR,8SR,11RS)-11-(benzoyloxy)tricyclot[6.2.2.01,6]dodecan-9-one