We wanted our interface to produce a protein that would inhibit the development of Staphylococcus aureus in the environment of the implant, and we wanted this peptide (RNA III inhibiting peptide) to be secreted from cytoplasm to the extracellular medium.

We decided to modify the Biobrick BBa_K237002 from iGEM SDU-Denmark 2009 Team. This Biobrick enables expression of RNAIII inhibiting peptide, we improved it by adding a secretion signal peptide to adress RIP to Escherichia coli Type II Secretion System and optimizing it for our chassis E. coli BL21 (DE3) pLysS strain.

Following the advice of Dr. Jean-Michel Betton, Research Director in the Structural Biology Department at the Institut Pasteur, we chose to try two different signal sequences to export our peptides, which he knew about and which are known to be efficient: MalE and DsbA. Once in the periplasm, due to the small size of RIP (7 amino acids), a leaky release through the outer membrane of the bacteria should allow us to obtain RIP in the medium [6].

Figure 1: Schematic diagram of BBa_K2616001