IGEM:Imperial/2010/Fast Response module/Bilins

Overview

Bilins are a versatile colour output, with well understood biosynthetic pathways. Many intermediate steps are colourless, so an enzyme used in the penultimate step of the pathway (for example) could be deactivated until the reception of an input signal. However the pathways are long, and the response time is unknown.

The concept was to have the pathway produce a colourless precursor, which would accumulate in the cell. The enzyme for the final step in the pathway would be produced as a polypeptide and cleaved by a protease, that is activated by an external signal. The problem with this method was the uncertainty that the enzyme would be inactive when it is in polypeptide form or that it would re-fold correctly when cleaved.

Papers

• Glazer. Light guides. Directional energy transfer in a photosynthetic antenna. J Biol Chem (1989)

Not particularly relevant, more concerned with the absorption and energy transfer, not emittance.

• Stoll and Gray. The preparation and characterization of bile pigments. Biochemical Journal (1977)

Again, not particularly relevant. Looks at the chemicals from a chemistry perspective, not their biosynthesis.

• Gambetta and Lagarias. Genetic engineering of phytochrome biosynthesis in bacteria. Proceedings of the National … (2001)

Discusses two enzymes that function as the final steps of biosynthesis, however still requires the presence of heme in the cell. May be more useful information here, so needs to be read fully when the focus is on output again.

• Beale. Biosynthesis of phycobilins. Chemical Reviews (1993)

Looks interesting, needs to be read fully. Seems to be dependant upon heme presence again.

There was one final paper that still needs to be referenced, which discussed the synthesis of heme. At first sight it seems far too complicated to implement.