Module #3, Protein Expression and Purification: After identification using FBDD, the hit compounds must be screened against a recombinant form of the target protein using a biophysical assay. In this module, students prepared recombinant Goα protein with an N-terminal 6xHis and Maltose Binding Protein (MBP) tag with a Tobacco Etch Virus (TEV) cleavage site, which was overexpressed in E. coli BL21 (DE3) cells. The E. coli cultures were harvested the following day after sufficient growth and induction with isopropyl-D-1-thiogalactopyranoside (IPTG).