Engineering BmpA as a carrier for surface display of IgG-binding domain on Lactococcus lactis.

Basic membrane protein A (BmpA) is a potential carrier protein for surface display of the IgG-binding domain on Lactococcus lactis. We have shown that it can increase the adhesion of bacteria to the intestinal cell model by 1.3-fold and have improved BmpA-based surface display by engineering the BmpA molecule. The bulk of the BmpA molecule was shown to be important in surface display; however, limited shortening (variant Bmp1) resulted in a large increase in the surface display ability. The closeness of the N- and the C-terminals in the Bmp1 model and the inefficiency of the spacer suggest that the distance of the passenger from the membrane is not of prime importance in surface display.