Part:BBa_K4247024

Orf438 and Tyrosinase operon [Streptomyces antibioticus]

This composite part codes for orf438 (BBa_K4247022) and the tyrosinase enzyme (BBa_K4247023) of Streptomyces antibioticus. Orf438 is indispensable for the functioning of S. antibioticus tyrosinase according to Bernan et al., 1985 and was used by Choi et al., 2012 to activate this enzyme in a co-expression system.

Usage and Biology

The enzyme tyrosinase is an oxidase found across taxa. It contains copper and is well known for its tyrosine modifying step which gives melanin. Our project specifically focused on converting the tyrosines of mfp151 (parts BBa_K4247020, BBa_K4247021) into DOPA in E.coli, a post-translational modification that makes mfp151 sticky. A way to achieve this dopaquinone conversion is by first producing mfp151 in vitro and then expose it to tyrosinase. But, this method has the limitations of having to purify the enzymes and of not allowing the DOPA modification to occur in the tyrosines that are not exposed to the enzyme. To overcome these limitations, we focused on developing a co-expression system where E.coli would co-express 2 plasmids, one with mfp151 and another with tyrosinase along with its copper cofactor (orf438). Upon induction of both plasmids with IPTG, the tyrosines incorporated in the mfp151 protein would be hydroxylated to DOPA, thus making the mfp151 protein adhesive.