Expression and purification of the mitochondrial transmembrane protein FAM210A in Escherichia coli

The protein Family with sequence similarity 210 member A (FAM210A) is a mitochondrial inner membrane protein that regulates the protein synthesis of mitochondrial DNA encoded genes. However, how it functions in this process is not well understood. Developing and optimizing a protein purification strategy will facilitate biochemical and structural studies of FAM210A. Here, we developed a method to purify human FAM210A with deleted mitochondrial targeting signal sequence using the MBP-His(10) fusion in Escherichia coli. The recombinant FAM210A protein was inserted into the E. coli cell membrane and purified from isolated bacterial cell membranes, followed by a two-step process using Ni-NTA resin-based immobilized-metal affinity chromatography (IMAC) and ion exchange purification. A pulldown assay validated the functionality of purified FAM210A protein interacting with human mitochondrial elongation factor EF-Tu in HEK293T cell lysates. Taken together, this study developed a method for purification of the mitochondrial transmembrane protein FAM210A partially complexed with E.coli derived EF-Tu and provides an opportunity for future potential biochemical and structural studies of recombinant FAM210A protein.