Download Artemisinin

Production of Artemisinic acid
using engineered yeast
Journal Club I
7th July 09
David Roche
Charles Fracchia
Summary

Introduction

Materials and Methods
Identifying the genes involved in Artemisinin production

Results

Concept of feedback

Discussion

How is it relevant to SB?

Conclusions
Introduction

Artemisinin is anti-malarial compound

Currently extracted from the wormwood plant
– but not efficient or cheap enough

Copied the biosynthetic pathways into the yeast
Materials and Methods
Green: engineered
pathways
 Blue: directly
upregulated
 Purple: indirectly
upregulated

Materials and Methods
Increased FPP
production by
upregulating FPP
synthases and
downregulating to
convertases
 Introduced ADS
 Cloned P450

M&M: Identifying the ADS genes
They supposed that
the enzymes shown in
green shared
common ancestor
enzymes
 Compared the genes
using BLAST and
identified one P450
gene with high
homology

Results
50%
2x
5x
The concept of feedback
inhibition/activation

Metabolic flux relies on regulation
Discussion

Increase in yield and decrease in
production costs

General principle can be applied to
production of other compounds, e.g. Taxol
– an anti cancer drug, which is normally
extracted from the Pacific yew tree.

Good example of metabolic engineering to
give a useful product.
Discussion

Laborious process of specially engineering
each step.

Not necessarily easily reproducible. To reengineer for other compounds, must go
‘back to the drawing board.’

Yield optimization and industrial scale-up
still required to reduce prices significantly
below their current level.
How is it relevant to SB?

Previous strategies in metabolic engineering seem more
of an art with experimentation by trial-and-error.

Keasling approach to the problem was more in line with
the principles of Synthetic Biology, using a logical
approach for the design.

Used computational modelling to investigate the most
efficient mRNA sequence for maximal compound
production
Conclusions

Materials and Methods
Duplicate genes
Knockout genes
Genetic insertion

Results
50% increase for duplication
2x increase for knockout
5x increase for gene insertion

Concept of feedback
Products of a reaction can control
their own conversion

Discussion
Engineered approach to metabolic engineering.
Basic method can be applied to production of other
compounds.