Plant terpenoid synthases: Molecular biology and phylogenetic analysis

Abstract

This review focuses on the monoterpene, sesquiterpene, and diterpene synthases of plant origin that use the corresponding C 10 , C 15 , and C 20 prenyl diphosphates as substrates to generate the enormous diversity of carbon skeletons characteristic of the terpenoid family of natural products. A description of the enzymology and mechanism of terpenoid cyclization is followed by a discussion of molecular cloning and heterologous expression of terpenoid synthases. Sequence relatedness and phylogenetic reconstruction, based on 33 members of the Tps gene family, are delineated, and comparison of important structural features of these enzymes is provided. The review concludes with an overview of the organization and regulation of terpenoid metabolism, and of the biotechnological applications of terpenoid synthase genes.The pathways of monoterpene, sesquiterpene, and diterpene biosynthesis are conveniently divided into several stages. The first encompasses the synthesis of isopentenyl diphosphate, isomerization to dimethylallyl diphosphate, prenyltransferase-catalyzed condensation of these two C 5 -units to geranyl diphosphate (GDP), and the subsequent 1Ј-4 additions of isopentenyl diphosphate to generate farnesyl (FDP) and geranylgeranyl (GGDP) diphosphate ( Fig. 1) (1). In the second stage, the prenyl diphosphates undergo a range of cyclizations based on variations on the same mechanistic theme to produce the parent skeletons of each class. Thus, GDP (C 10 ) gives rise to monoterpenes (2), FDP (C 15 ) to sesquiterpenes (3), and GGDP (C 20 ) to diterpenes (4). These transformations catalyzed by the terpenoid synthases (cyclases) may be followed by a variety of redox modifications of the parent skeletal types to produce the many thousands of different terpenoid metabolites of the essential oils, turpentines, and resins of plant origin (5).This review focuses on the synthases that use prenyl diphosphate substrates to generate the enormous diversity of carbon skeletons characteristic of terpenoids. Most of these natural products are cyclic, and many contain multiple ring systems, the basic structures of which are determined by the highly specific terpenoid synthases; examples of synthases that produce acyclic products are also known. The terpenoid synthases may be involved in the regulation of pathway flux because they operate at metabolic branch points and catalyze the first committed steps leading to the various terpene classes (6). The synthases responsible for generating the parent compounds of the various types are quite similar in properties (7), and all operate by electrophilic reaction mechanisms, as do the prenyltransferases (8, 9). Comprehensive treatment of the topic, especially enzymological and mechanistic aspects, has been provided recently (2-4), and the field is periodically surveyed (10, 11). After brief coverage of the three types of terpene synthases from higher plants, with emphasis on common features of structure and function, we focus here on molecular cloning and sequence analysis of these ...

Studies on Biosynthetic Genes and Enzymes of Isoprenoids Produced by Actinomycetes

“…Isoprenoid cyclases are classified into two major types based on their modes of cyclization [9,20]. One type of cyclization (Fig.…”

“…3), followed by a variety of modifications, such as hydroxylation, methylation, and glycosylation, etc., to give rise to thousands of different isoprenoid metabolites. Therefore, the first key enzymes leading to the diversity of isoprenoids are isoprenoid cyclases.Isoprenoid cyclases are classified into two major types based on their modes of cyclization [9,20]. One type of cyclization (Fig.…”

Biosynthesis of plant‐derived flavor compounds

“…Much of the progress achieved in recent years in terpenoid metabolism is described elsewhere in this issue (Bohlmann and Keeling, 2008). Many terpene synthases have been isolated and characterized from various plant species (Bohlmann et al, 1998;Tholl, 2006). While many terpene volatiles are direct products of terpene synthases, many others are formed through transformation of the initial products by oxidation, dehydrogenation, acylation and other reactions (Croteau and Karp, 1991;Croteau et al, 2000;Dudareva et al, 2004;Pichersky et al, 2006).…”

Overproduction, purification and characterization of FtmPT1, a brevianamide F prenyltransferase from Aspergillus fumigatus

“…Trans-prenyltransferases (Bohlmann et al, 1998;Liang et al, 2002;Sacchettini & Poulter, 1997) are involved in the biosynthesis of terpenoids from C-5 units. These enzymes usually contain one or more prenyl diphosphate binding motifs, (N/D)DXXD, in their sequences (Bohlmann et al, 1998;Liang et al, 2002;Sacchettini & Poulter, 1997).…”

“…These enzymes usually contain one or more prenyl diphosphate binding motifs, (N/D)DXXD, in their sequences (Bohlmann et al, 1998;Liang et al, 2002;Sacchettini & Poulter, 1997). Their enzymic reaction depends strictly on the presence of metal ions such as Mg 2+ or Mn 2+ (Bohlmann et al, 1998;Liang et al, 2002). A special group of prenyltransferases catalyses the attachment of a prenyl moiety to an aromatic nucleus.…”