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Multi-Substrate Terpene Synthases: Their Occurrence and Physiological Significance.

Pazouki L, Niinemets Ü - Front Plant Sci (2016)

Bottom Line: Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15), and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5), mono- (C10), and diterpenes (C20).Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases.This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Physiology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences Tartu, Estonia.

ABSTRACT
Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15), and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5), mono- (C10), and diterpenes (C20). Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases. This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated. Multi-substrate use could lead to important changes in terpene product profiles upon substrate profile changes under perturbation of metabolism in stressed plants as well as under certain developmental stages. We therefore argue that multi-substrate use can be significant under physiological conditions and can result in complicate modifications in terpene profiles.

No MeSH data available.


Related in: MedlinePlus

Phylogenetic tree of terpene synthases (TPS) with confirmed capacity for multi-substrate use (Table 1 for details of product and substrate specificities). The red branch denotes TPS with C5/C10 activity, the black branches with C10/C15 activity, the blue branches with C10/C15/C20 activity, and the green branches with C15/C20 activity. These 40 multi-substrate terpene synthase are from different TPS families including TPS-a, TPS-b, TPS-g, TPS-d, TPS-e, and TPS-f. The tree was constructed by MEGA5 software by UPGMA method (Tamura et al., 2011). The asterisks denote the presence of the conserved arginine-rich RRx8W motif at the N-terminal of the protein that is common in many monoterpene synthases (Chen et al., 2011). The underlined enzymes demonstrate the presence of transit peptide.
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Figure 2: Phylogenetic tree of terpene synthases (TPS) with confirmed capacity for multi-substrate use (Table 1 for details of product and substrate specificities). The red branch denotes TPS with C5/C10 activity, the black branches with C10/C15 activity, the blue branches with C10/C15/C20 activity, and the green branches with C15/C20 activity. These 40 multi-substrate terpene synthase are from different TPS families including TPS-a, TPS-b, TPS-g, TPS-d, TPS-e, and TPS-f. The tree was constructed by MEGA5 software by UPGMA method (Tamura et al., 2011). The asterisks denote the presence of the conserved arginine-rich RRx8W motif at the N-terminal of the protein that is common in many monoterpene synthases (Chen et al., 2011). The underlined enzymes demonstrate the presence of transit peptide.

Mentions: After these first reports of multi-substrate use, knowledge of plant TPSs capable of forming terpenes of different chain length depending on substrate has been steadily increasing, and to our knowledge, there are by now at least 40 confirmed cases of multi-substrate use among plant terpenoids (Table 1). Additionally enzymes that can use C10 and C15 substrates as all the synthases mentioned above, there are enzymes that can use C5 and C10 substrates (simultaneous hemi- and monoterpene synthase activities), C10–C20 substrates (simultaneous mono-, sesqui,- and diterpene synthase activities), and C15 and C20 activity (simultaneous sesqui- and diterpene synthase activities; Table 1, Figure 2). Among these different synthases, about 80% belong to C10/C15 multi-substrate enzymes (Figure 2), and most seem to be functionally active in the cytosol as the chloroplast-targeting peptide (or mitochondrial-targeting peptide) is present only in less than one third of the proteins (12 proteins, Table 1, Figure 2). Although the putative transit peptide might be present, the homology of transit peptides is generally low, making it difficult to predict the actual subcellular targeting, and thus, its presence does not constitute the absolute proof or protein targeting to plastids (Aharoni et al., 2004). Immunolabeling and generation of fluorescent fusion proteins can ultimately solve the issue with localization, but such studies have been rare in multi-substrate enzymes (Huang et al., 2009; Carrie and Small, 2013).


Multi-Substrate Terpene Synthases: Their Occurrence and Physiological Significance.

Pazouki L, Niinemets Ü - Front Plant Sci (2016)

Phylogenetic tree of terpene synthases (TPS) with confirmed capacity for multi-substrate use (Table 1 for details of product and substrate specificities). The red branch denotes TPS with C5/C10 activity, the black branches with C10/C15 activity, the blue branches with C10/C15/C20 activity, and the green branches with C15/C20 activity. These 40 multi-substrate terpene synthase are from different TPS families including TPS-a, TPS-b, TPS-g, TPS-d, TPS-e, and TPS-f. The tree was constructed by MEGA5 software by UPGMA method (Tamura et al., 2011). The asterisks denote the presence of the conserved arginine-rich RRx8W motif at the N-terminal of the protein that is common in many monoterpene synthases (Chen et al., 2011). The underlined enzymes demonstrate the presence of transit peptide.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4940680&req=5

Figure 2: Phylogenetic tree of terpene synthases (TPS) with confirmed capacity for multi-substrate use (Table 1 for details of product and substrate specificities). The red branch denotes TPS with C5/C10 activity, the black branches with C10/C15 activity, the blue branches with C10/C15/C20 activity, and the green branches with C15/C20 activity. These 40 multi-substrate terpene synthase are from different TPS families including TPS-a, TPS-b, TPS-g, TPS-d, TPS-e, and TPS-f. The tree was constructed by MEGA5 software by UPGMA method (Tamura et al., 2011). The asterisks denote the presence of the conserved arginine-rich RRx8W motif at the N-terminal of the protein that is common in many monoterpene synthases (Chen et al., 2011). The underlined enzymes demonstrate the presence of transit peptide.
Mentions: After these first reports of multi-substrate use, knowledge of plant TPSs capable of forming terpenes of different chain length depending on substrate has been steadily increasing, and to our knowledge, there are by now at least 40 confirmed cases of multi-substrate use among plant terpenoids (Table 1). Additionally enzymes that can use C10 and C15 substrates as all the synthases mentioned above, there are enzymes that can use C5 and C10 substrates (simultaneous hemi- and monoterpene synthase activities), C10–C20 substrates (simultaneous mono-, sesqui,- and diterpene synthase activities), and C15 and C20 activity (simultaneous sesqui- and diterpene synthase activities; Table 1, Figure 2). Among these different synthases, about 80% belong to C10/C15 multi-substrate enzymes (Figure 2), and most seem to be functionally active in the cytosol as the chloroplast-targeting peptide (or mitochondrial-targeting peptide) is present only in less than one third of the proteins (12 proteins, Table 1, Figure 2). Although the putative transit peptide might be present, the homology of transit peptides is generally low, making it difficult to predict the actual subcellular targeting, and thus, its presence does not constitute the absolute proof or protein targeting to plastids (Aharoni et al., 2004). Immunolabeling and generation of fluorescent fusion proteins can ultimately solve the issue with localization, but such studies have been rare in multi-substrate enzymes (Huang et al., 2009; Carrie and Small, 2013).

Bottom Line: Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15), and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5), mono- (C10), and diterpenes (C20).Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases.This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Physiology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences Tartu, Estonia.

ABSTRACT
Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15), and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5), mono- (C10), and diterpenes (C20). Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases. This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated. Multi-substrate use could lead to important changes in terpene product profiles upon substrate profile changes under perturbation of metabolism in stressed plants as well as under certain developmental stages. We therefore argue that multi-substrate use can be significant under physiological conditions and can result in complicate modifications in terpene profiles.

No MeSH data available.


Related in: MedlinePlus