Fig. 5
Substrate specificity of PtTPS19 and PtTPS20. a Model of PtTPS19 showing their three domain structure (yellow: γ-domain, brown: β-domain, green: α-domain). b Model of the aligned active sites of PtTPS19 and PtTPS20. The conserved DDxxD motif is shown as blue sticks and the NDxxTxxxE/DDxxSxxxE motif is represented by purple sticks. Met607 of PtTPS19 and Thr607 of PtTPS20, which influence product outcome, are depicted as red and yellow sticks, respectively. Product formation of wild type enzymes (c) and enzymes possessing one amino acid exchange (d). The enzymes were expressed in E. coli, extracted, partially purified, and incubated with PtTPS17 and the substrate GGPP. Products were extracted with hexane and analyzed by GC-MS. 1, geranyllinalool; 2, copalol; 3, ent-kaurene; 4, ent-isokaurene; 5, 16α-hydroxy-ent-kaurane