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Overview Sensitivity Tuner --- Characterisation --- Modelling Colour Generators --- Carotenoids (Orange/Red) --- Melanin (Brown) --- Violacein (Purple/Green) The Future Safety

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Violacein Pigments

Background

Violacein Biosynthesis

The Violacein pigment is produced from L-tryptophan via a pathway involving five enzymes, VioA-E. This forms a purple colour which remains within the individual cell colonies. This synthesis pathway is shown below:

From P.R. August, T.H. Grossman, C. Minor, M.P. Draper, I.A. MacNeil, J.M. Pemberton, K.M. Call, d. Holt, and M. S. Osbourne, Sequence Analysis and Functional Characterization of the Violacein Biosynthetic Pathway from Chromobacterium violaceum, J. Mol. Microbiol. Biotechnol. (2000) 2(4): 513-519. [1]

The vioE is used in the step just after the vioB for the 1-2 shift of the indole ring. César Sánchez, Dr., Alfredo F. Braña, Prof. Dr., Carmen Méndez, Prof. Dr., José A. Salas, Prof. Dr. Reevaluation of the Violacein Biosynthetic Pathway and its Relationship to Indolocarbazole Biosynthesis [[2]]

Further, as module 5 is Aqua, expressing the genes under different promoters will allow us to produce at least two different colours. The Sanchez paper suggests that removing vioD can produce a dark blue, while removing vio C produces a dark green. Our actual results showed that the ABDE construct produced a dark green pigment while the ABCE produced light green.

Vio Operon

Our VioA-E genes are from Chromobacterium voilaceum ATCC 12472 in the pPSX vio+ plasmid. This was kindly provided by John Pemberton; Department of Microbiology and parasitology, University of Queensland, Brisbane, Australia. (Sarovich & Pemberton (2007) Plasmid 57:306-313)

• pPSX sequence ID FJ422118
• vio gene cluster complete cds AB032799 and AF172851.

Action plan of our team

Our action plan is as follows:

1. Test for violacein pigment production

2. Synthesize the violacein operon without any forbidden restriction sites. The finished gene will be BioBrick compatible and will have restriction sites around the vioC and vioD to remove these genes and form new colours.

3. Attach to the promoters of the processing system