7BZC

Crystal structure of plant sesterterpene synthase AtTPS18 complexed with farnesyl thiolodiphosphate (FSPP)

Summary for 7BZC

• Entry DOI: 10.2210/pdb7bzc/pdb
• Descriptor: Terpenoid synthase 18, MAGNESIUM ION, S-[(2E,6E)-3,7,11-TRIMETHYLDODECA-2,6,10-TRIENYL] TRIHYDROGEN THIODIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: terpenoid, terpene synthase, sesterterpene, cyclization mechanism, plant protein, lyase
• Biological source: Arabidopsis thaliana (Mouse-ear cress)
• Total number of polymer chains: 1
• Total formula weight: 69947.32

Authors

Li, J.X.,Wang, G.D.,Zhang, P. (deposition date: 2020-04-27, release date: 2020-09-23, Last modification date: 2023-11-29)

Primary citation

Chen, Q.,Li, J.,Liu, Z.,Mitsuhashi, T.,Zhang, Y.,Liu, H.,Ma, Y.,He, J.,Shinada, T.,Sato, T.,Wang, Y.,Liu, H.,Abe, I.,Zhang, P.,Wang, G.
Molecular Basis for Sesterterpene Diversity Produced by Plant Terpene Synthases.
Plant Commun., 1:100051-100051, 2020

PubMed Abstract: Class I terpene synthase (TPS) generates bioactive terpenoids with diverse backbones. Sesterterpene synthase (sester-TPS, C25), a branch of class I TPSs, was recently identified in Brassicaceae. However, the catalytic mechanisms of sester-TPSs are not fully understood. Here, we first identified three nonclustered functional sester-TPSs (AtTPS06, AtTPS22, and AtTPS29) in . AtTPS06 utilizes a type-B cyclization mechanism, whereas most other sester-TPSs produce various sesterterpene backbones via a type-A cyclization mechanism. We then determined the crystal structure of the AtTPS18-FSPP complex to explore the cyclization mechanism of plant sester-TPSs. We used structural comparisons and site-directed mutagenesis to further elucidate the mechanism: (1) mainly due to the outward shift of helix G, plant sester-TPSs have a larger catalytic pocket than do mono-, sesqui-, and di-TPSs to accommodate GFPP; (2) type-A sester-TPSs have more aromatic residues (five or six) in their catalytic pocket than classic TPSs (two or three), which also determines whether the type-A or type-B cyclization mechanism is active; and (3) the other residues responsible for product fidelity are determined by interconversion of AtTPS18 and its close homologs. Altogether, this study improves our understanding of the catalytic mechanism of plant sester-TPS, which ultimately enables the rational engineering of sesterterpenoids for future applications.

PubMed: 33367256
DOI: 10.1016/j.xplc.2020.100051

Experimental method

X-RAY DIFFRACTION (2.303 Å)