Part:BBa_K1078000

Mxr1 (methanol expression regulator 1) is a key regulator, at transcriptional level, of methanol metabolism in the methylotrophic yeast Pichia pastoris. It is a transcriptional factor that binds upstream of the MUT (methanol utilizing) pathway and peroxisome biogenesis gene´s promoters using its zinc finger domain. Among the MUT genes is the AOX1 gene that is regulated by the pAOX1 promoter. The pAOX promoter is found three times in the registry of parts; Part:BBa_K431007, Part:BBa_K945000, BBa_I764001, it is use for heterologous protein expression in Pichia.

The 14-3-3 proteins are ubiquitous, and have important roles in controlling a wide variety of cellular processes, like gene expression, metabolism, cell cycle and apoptosis. These 14-3-3 proteins are involved in the carbon source-dependent regulation of Mxr1, which is inactive in ethanol and glycerol, but is active in methanol.

Our submitted Mxr1 is mutated in order to NOT be repressed by methanol, as the original Mxr1 is. This is done by substituted the Ser215 of the protein with Ala, inactivating the 14-3-3 protein interaction (phosphorylation) with Mxr1. It is also smaller than the original Mxr1 because it was already reported that the major activation domain of Mxr1 is located into the first 400 amino acids.

The modified Mxr1 is able to activate the pAOX promoter in ethanol, glycerol and methanol. This is useful for our biosensor design, which aims to detect levels of methanol above 2% in common alcoholic drinks (normally containing 10 to 60% ethanol). This will allow the government to make a preliminary high-throughput screening of ethanol drinks tainted will methanol.