Production of Artemisinic Production of Artemisinic acid using engineered acid using engineered

yeastyeast

Journal Club I7th July 09

David RocheCharles Fracchia

SummarySummary Introduction

Results

Concept of feedback

Discussion

How is it relevant to SB?

Conclusions

Materials and MethodsIdentifying the genes involved in Artemisinin production

IntroductionIntroductionArtemisinin 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 MethodsMaterials and Methods

Green: engineered pathways

Blue: directly upregulated

Purple: indirectly upregulated

Materials and MethodsMaterials and Methods

Increased FPP production by upregulating FPP synthases and downregulating to convertases

Introduced ADSCloned P450

M&M: Identifying the ADS M&M: Identifying the ADS genesgenes

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

ResultsResults

5x

2x

50%

The concept of feedback The concept of feedback inhibition/activationinhibition/activation

Metabolic flux relies on regulation

DiscussionDiscussion 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.

DiscussionDiscussionLaborious process of specially

engineering each step.

Not necessarily easily reproducible. To re-engineer 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?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

ConclusionsConclusions Materials and Methods

Results

Concept of feedback

Discussion

Duplicate genes

Knockout genes

Genetic insertion

50% increase for duplication

2x increase for knockout

5x increase for gene insertion

Products of a reaction can control

their own conversion

Engineered approach to metabolic engineering.

Basic method can be applied to production of other compounds.