## 3 Results
### Homology Modeling and Molecular Docking of Pm TPSs  
The predicted Pm TPS structures, as shown in Figure 4, revealed that Pm TPSs comprised two structural domains, the N- and C-terminal, with each domain consisting of several \(\alpha\)-helices, \(\beta\)-sheets/turns, and random coils/loops. The C-terminal domain forms 9-17 \(\alpha\)-helices from helix A to helix K. The structures of helix C, helix D2, and helix H1 in Pm TPS (+)-\(\alpha\)-pinene, Pm TPS (-)-\(\beta\)-pinene, and Pm TPS limonene had 2-3 fewer amino acid residues than those in Pm TPS (-)-\(\alpha\)-pinene, Pm TPS selinee, and Pm TPS longifolene. Helix J is presented as a complete long helix (Pm TPS (+)-\(\alpha\)-pinene, Pm TPS (-)-\(\beta\)-pinene, and Pm TPS limonene) or equally divided into two short helices (Pm TPS (-)-\(\alpha\)-pinene, Pm TPS selinee, and Pm TPS longifolene), according to the template. Other \(\alpha\)-helices were conserved in all Pm TPSs. The results of [PERSON] plot evaluation (Figure S3) revealed that the structural score of Pm TPSs obtained via this modeling were of a high-quality model: 90.7%-94.8% of residues were found in the most favored region, 4.1%-8.2% of residues were found in additionally allowed regions, and 0.4%-1.5% of residues were found in generously allowed and disallowed regions. This justified the stability without any steric hindrance and reliance on the predicted model with acceptable qualities. All TPSs formed active pockets at the C-terminus, where GPP and FPP molecules form hydrogen bonds with different amino acid residues. The docking experiment showed that GPP and FPP could  
Figure 3: **(a)** Predicted secondary structure of Pm TPSs by SOMPA. Numbers represent amino acid residues. Blue indicates residues part of an \(\alpha\)-helix, green indicates those part of a \(\beta\)-sheet/turn, red indicates extended strands, and purple indicates residues in random coils; **(b)** Domain analysis of Pm TPSs using the SMART database, which predicted the presence of two domains that actively participate in the terpene biosynthesis reaction. The numbers on domain boxes represent amino acid residue positions, and the E-value is indicated in parentheses. bind to monoterpene and sesquiterpene synthases, respectively. The confidence scores of the six terpene synthases were 4, 4, 4, 4, 3, and 2 for Pm TPS (+)-\(\alpha\)-pinene, Pm TPS (\(-\))-\(\alpha\)-pinene, Pm TPS (\(-\))-\(\beta\)-pinene, Pm TPS limonee, Pm TPS simenene, and Pm TPS longifolene, respectively. The total scores were 7.23, 7.24, 6.31, 7.68, 7.32, and 5.98 for Pm TPS (+)-\(\alpha\)-pinene, Pm TPS (\(-\))-\(\alpha\)-pinene, Pm TPS (\(-\))-\(\beta\)-pinene, Pm TPS limonee, Pm TPS soleninee, and Pm TPS longifolene, respectively. Docking simulation results are shown in Figure 5. The side chains of aspartic acid (Asp) 484 and tyrosine (Tyr) 555 formed three hydrogen bonds and one hydrogen bond with the diphosphate group of GPP, respectively, in the substrate-binding pocket in Pm TPS (+)-\(\alpha\)-pinene. The amino acids Asp 484 and Tyr 555 are distributed in helices H2 and J, respectively. For Pm TPS (\(-\))-\(\alpha\)-pinene, four residues in the binding pocket form hydrogen bonds with GPP: the amino acid glutamine (Glu) 410 in the middle of helix F, the amino acid Glu 489 in the H2-\(\alpha\)1 loop, the amino acid serine (Ser) 432 in the G1-G2 loop, and the amino acid arginine (Arg) 473 in the middle of helix H2. The amino acid Arg 473, Glu 410, Glu 489, and Ser 432 formed three, two, two, and one hydrogen bonds with the diphosphate group of GPP, respectively. For Pm TPS (\(-\))-\(\beta\)-pinene, only hydrogen bonds were formed between the side chain of the amino acid threonine (Thr) 559, which is distributed in helix K, and the diphosphate group of GPP. For Pm TPS limonee, five residues in the binding pocket formed hydrogen bonds with GPP: cysteine (Cys) 343 and Asn 346 in helix D, the amino acid Tyr 319 in helix C, the amino acid Tyr 425 in helix F, and the amino acid Ser 451 near the end of helix G1.