Team:UNAM Genomics/Project/Description

Project description

To improve the biosynthesis of tetrahydrobiopterin in Escherichia coli, we are going to build the following genetic circuits:

• Three transcriptional units under the control of the lac promoter. This will serve as an internal control for us because it replicates the gene arrangement reported in Yamamoto, et al. [1].
• An operon with the first gene of the pathway at the end of the construction and an RBS upstream each gene. This is because E. coli has most of its genes organized as operons. Also, we will place GTP cyclohydrolase I at the end of it because we want it to be less expressed [2] in order to avoid inclusion bodies.
• Two transcriptional units. The first will have the second and third gene of the pathway under the sigma 70 promoter. The first gene of the pathway will be under the lac promoter. Again, and RBS will be placed upstream each gene. We expect to maintain an equilibrium of gene expression.

As a biosensor and biosafety feature we will replace tyrA, the default enzyme for tyrosine biosynthesis with the human analogue phenylalanine hydroxilase in order to turn our bacteria dependent of the system. In this way, auxotrophic E. coli will be complemented when producing BH4. So, we will have two-in-one!