generated hairy roots expressing the mutant enzyme and after in vitro feeding of
various strictosidine analogs, produced unnatural monoterpene indole alkaloids.
This study could not have been completed without data concerning the strictosidine
synthase crystal structure (Ma et al. 2006 ). The crystal structure of THCA synthase
has subsequently been reported (Shoyama et al. 2005 , 2012 ). Modification of the
amino acid residue(s) close to the CBGA binding site would enable recognition of
modified CBGA that might result in novel unnatural cannabinoids with different
biological activities.
8.4 Conclusions
The biosynthetic mechanism of cannabinoid production had long been uncertain,
mostly due to the lack of experimental evidence. In particular, the identification of
biosynthetic enzymes was essential in clarification of the pathway. Hence, over the
last two decades, various molecular, biochemical, and omics-based studies have
been conducted, identifying the majority of the enzymes and genes involved in the
cannabinoid pathway. Research on these enzymes has made considerable progress
in relation to understanding the biosynthetic mechanism involved in cannabinoid
production and has opened a route to the biotechnological application of biosyn-
thetic enzymes and genes, including (1) effective biomimetic production of
cannabinoids in heterologous hosts, (2) metabolic engineering to control cannabi-
noid content inCannabisplants for medicinal and industrial production purposes,
and (3) the rational design of the enzyme active site to improve or modify the
catalytic functions. These studies may actually be realized in the next decade as
several laboratories have already begun to explore the biotechnological potential of
cannabinoids.
Acknowledgements We would like to thank all the collaborators who contributed to our studies
on cannabinoid biosynthesis. Research in the corresponding author’s laboratory was partially
supported by grants from the Chulalongkorn Academic Advancement into Its 2nd Century Project
(to SS) and Thailand Research Fund RG578008 (to SS).
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8 Cannabinoids: Biosynthesis and Biotechnological Applications 201