Co-expression of squalene epoxidases with triterpene cyclases boosts production of triterpenoids in plants and yeast.
Metab Eng
; 49: 1-12, 2018 09.
Article
em En
| MEDLINE
| ID: mdl-30016654
ABSTRACT
Triterpene cyclases catalyze the first committed step in triterpene biosynthesis, by forming mono- to pentacyclic backbone structures from oxygenated C30 isoprenoid precursors. Squalene epoxidase precedes this cyclization by providing the oxygenated and activated substrate for triterpene biosynthesis. Three squalene epoxidases from Cucurbita pepo (CpSEs) were isolated and shown to have evolved under purifying selection with signs of sites under positive selection in their N- and C-termini. They all localize to the Endoplasmic Reticulum (ER) and produce 2,3-oxidosqualene and 2,322,23-dioxidosqualene when expressed in a yeast erg1 (squalene epoxidase) erg7 (lanosterol synthase) double mutant. Co-expression of the CpSEs with four different triterpene cyclases, either transiently in Nicotiana benthamiana or constitutively in yeast, showed that CpSEs boost triterpene production. CpSE2 was the best performing in this regard, which could reflect either increased substrate production or superior channeling of the substrate to the triterpene cyclases. Fluorescence Lifetime Imaging Microscopy (FLIM) analysis with C. pepo cucurbitadienol synthase (CpCPQ) revealed a specific interaction with CpSE2 but not with the other CpSEs. When CpSE2 was transformed into C. pepo hairy root lines, cucurbitacin E production was increased two folds compared to empty vector control lines. This study provides new insight into the importance of SEs in triterpene biosynthesis, suggesting that they may facilitate substrate channeling, and demonstrates that SE overexpression is a new tool for increasing triterpene production in plants and yeast.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
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Nicotiana
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Triterpenos
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Plantas Geneticamente Modificadas
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Liases Intramoleculares
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Citrullus
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Cucurbita
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Esqualeno Mono-Oxigenase
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Microrganismos Geneticamente Modificados
Idioma:
En
Revista:
Metab Eng
Assunto da revista:
ENGENHARIA BIOMEDICA
/
METABOLISMO
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Dinamarca