Expressing red fluorescent protein on the surface of Escherichia coli using C-terminal domain of autotransporters.

The Type V secretion system, or "autotransporter", is a secretion system that enables bacteria to directly export proteins from the cell interior to the extracellular membrane. mCherry is a second-generation monomeric red fluorescent protein that has an improvement in photostability compared to the first generation of RFP. In this research, we conducted the fusion of the mRFP into the C-terminal domain of EhaA - the translocation domain of the autotransporter protein transport system - to investigate the expression of mRFP on the surface of Escherichia coli , a model organism commonly utilized in recombinant protein research. The induction of the mRFP-EhaA C-terminal domain complex expression was achieved using isopropyl β-D-1-thiogalactopyranoside (IPTG) and confirmed through SDS-PAGE stained with Coomassie Brilliant Blue and Western blotting using anti-6X His tag antibodies. The surface expression of the mRFP-EhaA C-terminal complex protein was validated through the fluorescent properties of mRFP and further confirmed using fluorescent microscopy. This study laid the groundwork for surface expression on cost-effective Gram-negative bacteria, E. coli.