Expression and Purification of Arabidopsis Transmembrane Protein BCM1 in Saccharomyces cerevisiae

Heterologous expression and purification of transmembrane proteins have remained a challenge for decades hampering detailed biochemical and structural characterization of key enzymes and their interacting regulators in multiple metabolic pathways. An in-depth study on the newly identified Arabidopsis thaliana integral membrane protein BALANCE OF CHLOROPHYLL METABOLISM 1 (BCM1) showed a stimulatory effect of the BCM1 on magnesium chelatase, the first enzyme of chlorophyll biosynthesis, through interaction with the GENOMES UNCOUPLED 4 ( Wang et al., 2020 ). Here, we report a detailed and optimized method for heterologous expression and purification of His-tagged BCM1 in Saccharomyces cerevisiae. Following this method, we obtained native BCM1 used for in vitro enzymatic assay of magnesium chelatase ( Wang et al., 2020 ). Currently, the crystallization studies of the BCM1 are underway. This protocol could be adapted to purify BCM1-like transmembrane proteins from eukaryotic organisms for enzymatic and structural studies.