8H4P

class I sesquiterpene synthase

Summary for 8H4P

• Entry DOI: 10.2210/pdb8h4p/pdb
• Descriptor: Longiborneol synthase CLM1, PYROPHOSPHATE, N-benzyl-N,N-diethylethanaminium, ... (5 entities in total)
• Functional Keywords: class i sesquiterpene synthase, structural protein
• Biological source: Gibberella zeae (strain ATCC MYA-4620 / CBS 123657 / FGSC 9075 / NRRL 31084 / PH-1) (Wheat head blight fungus, Fusarium graminearum)
• Total number of polymer chains: 2
• Total formula weight: 78786.53

Authors

Li, A.N.,Lou, T.T.,Ma, M. (deposition date: 2022-10-11, release date: 2023-08-23)

Primary citation

Lou, T.,Li, A.,Xu, H.,Pan, J.,Xing, B.,Wu, R.,Dickschat, J.S.,Yang, D.,Ma, M.
Structural Insights into Three Sesquiterpene Synthases for the Biosynthesis of Tricyclic Sesquiterpenes and Chemical Space Expansion by Structure-Based Mutagenesis.
J.Am.Chem.Soc., 2023

PubMed Abstract: The cyclization of farnesyl diphosphate (FPP) into highly strained polycyclic sesquiterpenes is challenging. We here determined the crystal structures of three sesquiterpene synthases (STSs, namely, BcBOT2, DbPROS, and CLM1) catalyzing the biosynthesis of the tricyclic sesquiterpenes presilphiperfolan-8β-ol (), Δ-protoilludene (), and longiborneol (). All three STS structures contain a substrate mimic, the benzyltriethylammonium cation (BTAC), in their active sites, providing ideal templates for quantum mechanics/molecular mechanics (QM/MM) analyses toward their catalytic mechanisms. The QM/MM-based molecular dynamics (MD) simulations revealed the cascade reactions toward the enzyme products, and different key active site residues that play important roles in stabilizing reactive carbocation intermediates along the three pathways. Site-directed mutagenesis experiments confirmed the roles of these key residues and concomitantly resulted in 17 shunt products (-). Isotopic labeling experiments addressed the key hydride and methyl migrations toward the main and several shunt products. These combined methods provided deep insights into the catalytic mechanisms of the three STSs and demonstrated how the chemical space of STSs can rationally be expanded, which may facilitate applications in synthetic biology approaches toward pharmaceutical and perfumery agents.

PubMed: 37018048
DOI: 10.1021/jacs.3c00278

Experimental method

X-RAY DIFFRACTION (1.47 Å)