Publications

• Stilbene synthase from Scots pine (Pinus sylvestris).

  Schanz S., Schroeder G., Schroeder J.

  Stilbene synthases are named according to their substrate preferences. By this definition, enzymes preferring cinnamoyl-CoA are pinosylvin synthases, and proteins with a preference for phenylpropionyl-CoA are dihydropinosylvin synthases. We investigated the assignment of a stilbene synthase cloned ... >> More

  Stilbene synthases are named according to their substrate preferences. By this definition, enzymes preferring cinnamoyl-CoA are pinosylvin synthases, and proteins with a preference for phenylpropionyl-CoA are dihydropinosylvin synthases. We investigated the assignment of a stilbene synthase cloned from Scots pine (Pinus sylvestris) as dihydropinosylvin synthase and the proposal of an additional pinosylvin synthase [1992, Plant Mol. Biol. 18, 489-503]. The results show that the previous interpretation was misled by several unexpected factors. Firstly, we found that the substrate preference and the activity of the plant-specific protein expressed in E. coli was influenced by bacterial factors. This was reduced by improvement of the expression system, and the subsequent kinetic analysis revealed that cinnamoyl-CoA rather than phenylpropionyl-CoA is the preferred substrate of the cloned stilbene synthase. Secondly, mixing experiments showed that extracts from P. sylvestris contain factor(s) which selectively influenced the substrate preference, i.e. the activity was reduced with phenylpropionyl-CoA, but not with cinnamoyl-CoA. This explained the apparent differences between plant extracts and the cloned enzyme expressed in E. coli. Taken together, the results indicate that the cloned enzyme is a pinosylvin synthase, and there is no evidence for a second stilbene synthase. This study cautions that factors in the natural and in new hosts may complicate the functional identification of cloned sequences. << Less

  FEBS Lett. 313:71-74(1992) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• An aldol switch discovered in stilbene synthases mediates cyclization specificity of type III polyketide synthases.

  Austin M.B., Bowman M.E., Ferrer J.-L., Schroeder J., Noel J.P.

  Stilbene synthase (STS) and chalcone synthase (CHS) each catalyze the formation of a tetraketide intermediate from a CoA-tethered phenylpropanoid starter and three molecules of malonyl-CoA, but use different cyclization mechanisms to produce distinct chemical scaffolds for a variety of plant natur ... >> More

  Stilbene synthase (STS) and chalcone synthase (CHS) each catalyze the formation of a tetraketide intermediate from a CoA-tethered phenylpropanoid starter and three molecules of malonyl-CoA, but use different cyclization mechanisms to produce distinct chemical scaffolds for a variety of plant natural products. Here we present the first STS crystal structure and identify, by mutagenic conversion of alfalfa CHS into a functional stilbene synthase, the structural basis for the evolution of STS cyclization specificity in type III polyketide synthase (PKS) enzymes. Additional mutagenesis and enzymatic characterization confirms that electronic effects rather than steric factors balance competing cyclization specificities in CHS and STS. Finally, we discuss the problematic in vitro reconstitution of plant stilbenecarboxylate pathways, using insights from existing biomimetic polyketide cyclization studies to generate a novel mechanistic hypothesis to explain stilbenecarboxylate biosynthesis. << Less

  Chem. Biol. 11:1179-1194(2004) [PubMed] [EuropePMC]

• Molecular and enzymatic characterization of two stilbene synthases from Eastern white pine (Pinus strobus). A single Arg/His difference determines the activity and the pH dependence of the enzymes.

  Raiber S., Schroeder G., Schroeder J.

  Pinus strobus (Eastern white pine) contains stilbenes biosynthetically derived from cinnamoyl-CoA (pinosylvin) or dihydrocinnamoyl-CoA (dihydropinosylvin). We screened a P. strobus cDNA library with a stilbene synthase (STS) probe from Pinus sylvestris. The eight isolated cDNAs represented two clo ... >> More

  Pinus strobus (Eastern white pine) contains stilbenes biosynthetically derived from cinnamoyl-CoA (pinosylvin) or dihydrocinnamoyl-CoA (dihydropinosylvin). We screened a P. strobus cDNA library with a stilbene synthase (STS) probe from Pinus sylvestris. The eight isolated cDNAs represented two closely related STS genes with five amino acid differences in the proteins. The enzyme properties were investigated after heterologous expression in Escherichia coli. Both proteins preferred cinnamoyl-CoA against dihydrocinnamoyl-CoA and thus represented pinosylvin synthases. Otherwise they revealed large differences. STS1 had only 3-5% of the activity of STS2, its pH optimum was shifted to lower values (pH 6), and it synthesized with cinnamoyl-CoA a second unknown product. Site-directed mutagenesis demonstrated that a single Arg-to-His exchange in STS1 was responsible for all of the differences. The proton acceptor properties of His are discussed as the reason for the properties of STS1. << Less

  FEBS Lett. 361:299-302(1995) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Molecular analysis of chalcone and dihydropinosylvin synthase from Scots pine (Pinus sylvestris), and differential regulation of these and related enzyme activities in stressed plants.

  Fliegmann J., Schroeder G., Schanz S., Britsch L., Schroeder J.

  Chalcone synthase (CHS) and stilbene synthase (STS) are closely related polyketide synthases which are key enzymes in the biosynthesis of flavonoids and stilbenes. Scots pine (Pinus sylvestris) is an interesting plant for a direct comparison of the enzymes. It not only contains the usual flavonoid ... >> More

  Chalcone synthase (CHS) and stilbene synthase (STS) are closely related polyketide synthases which are key enzymes in the biosynthesis of flavonoids and stilbenes. Scots pine (Pinus sylvestris) is an interesting plant for a direct comparison of the enzymes. It not only contains the usual flavonoids, but also an unusual chalcone derivative (pinocembrin), and it synthesizes stilbenes of the pinosylvin type. We analysed a CHS and a STS by molecular cloning and functional expression in Escherichia coli. The CHS was active not only with 4-coumaroyl-CoA (to naringenin chalcone), but also with cinnamoyl-CoA (leading to pinocembrin). The STS was identified as dihydropinosylvin synthase, because it preferred dihydrocinnamoyl-CoA to cinnamoyl-CoA. The protein deviated in 47 positions from the CHS consensus. It had 73.2% identity with the CHS from P. sylvestris and only 65.3% with a STS from peanut (Arachis hypogaea). We also investigated the regulation of both enzyme types in P. sylvestris plantlets exposed to stress. CHS was present in non-stressed plantlets, and induction led to a transient increase with a peak after 16 h. STS type activities were regulated differently and were absent in non-stressed plantlets. Increases were observed after a lag period of at least 6 h, and highest activities were obtained after 30 h. The analysis of the reactions in the plant extracts and the substrate specificity of the cloned STS indicate that the plants contain at least two different types of STS: the cloned dihydropinosylvin synthase and a pinosylvin synthase which preferentially utilizes cinnamoyl-CoA as substrate. << Less

  Plant Mol. Biol. 18:489-503(1992) [PubMed] [EuropePMC]