With Dr. Jung Hoon Ahn as the leader, our lab specializes on researching about the secretory production of proteins using microorganisms, especially using the bacterium Pseudomonas fluorescens. Our system of producing proteins is special in that the bacteria secretes the protein to the cell culture media. This greatly simplifies the process of obtaining useful proteins in that we do not have to go through processes that would normally take days and nights.
The secret of our secretion system is the TliDEF ABC Transporter that hydrolyzes ATP in exchange for translocation of proteins. For recognition of the protein for secretion, a signal sequence is attached to the target protein. On the scheme below, Green fluorescent protein (GFP) has a signal attached to it, and the TliDEF ABC Transporter (blue rectangles) recognizes the signal sequence, consequently secreting the GFP fusion protein to the outer membrane (OM) from the inner membrane (IM).
Many useful proteins have been secreted using the tliDEF ABC transporter. They include; alkaline phosphatase (AP), green fluorescens protein (GFP), thermostable lipase (TliA), epidermal growth factor (EGF) to name a few. In the future, we hope that the ABC Transporter could provide a simple way to scientists in secreting diverse recombinant proteins.