Phase II

Design

The purpose of phase II is to optimize the expression of the proteins necessary for the production of crocin glycosides and safranal. Unfortunately, ZCD has been shown to produce inclusion bodies when expressed'' in vivo'' in ''E. coli'' and so an alternative method needed to be developed to create a functional protein. This was done by following the technique described by Florence Bouvier (The Plant Cell, vol. 15 47-62).

Results

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Gene Design

BioBrick Prefix/Suffix
The Biobrick prefix and suffix were added to our gene so that they could be biobricked onto any biobrick plasmid with ease.


ZCD
This gene is from the organism Crocus sativus. This gene is only found in the Crocus species that produce this unique spice naturally. Thus, this gene is certainly necessary. We put this gene first because it is the first enzyme to cleave zeaxanthin to crocin dialdehyde, the precursor to crocin glycosides (the primary pigment of Saffron), and hydroxy-beta-cyclocitral, the precursor to picrocin and safranal (a significant portion of the aroma of saffron). Since CrtZ has an endogenous ortholog in Synechocystis, CrtR, we decided to put this gene last.

UGTCS2
This gene is also from Crocus sativus. We chose it for a similar reason to that of ZCD. This gene produces picrocin from hydroxy-beta-cyclocitral and crocin glycosides from crocin dialdehyde. Picrocin naturally degrades to saffranal. Thus, this enzyme finishes the production of our desired compounds.

Terminator
We chose a small, efficient (85%) terminator from the parts registry.

We optimized the construct for Synechocystis PCC 6803 using a program from DNA 2.0. We submitted the gene to DNA 2.0 to further evaluate and synthesize. DNA 2.0 provided the service of analyzing secondary structure of the gene near the RBS to help ensure successful translation.