Autodisplay is a genetic engineering technique that is used to insert a protein of interest on the outer surface of gram-negative bacteria. This technique has been developed into a cost-effective bioanalytical tool by Creative BioMart's technical team. Presently, we have successfully applied bacterial autodisplay in surface plasmon resonance chips (SPR) and ELISA assays for the identification of binding partners, like inhibitors, activators, biomarkers or autoantigens.
Autodisplay is a powerful bioanalytical tool because
Proteins or enzymes displayed on the surface of E. coli can directly interact with their binding partners. The post-displaying bacterial cell can be directly adhered to functionalize solid surfaces (microtiter plates, for instance) to facilitate the set-up of binding studies.
If the whole cell is not suitable, the outer membrane carrying heterologous proteins/enzymes can be stripped from the cell body for coating. This is particularly beneficial when the surface is hydrophobic, because the asymmetric assembly of the outer film enables the orientation to be controlled in this way, i.e. the inner part of the outer film faces the surface.
Presently, we have successfully applied bacterial autodisplay in SPR and ELISA assays.
Using molecular biology technology, we fused the Z domain of protein A with the coding region of AIDA-I protein, so that protein A could be expressed on the outer membrane of E.coli. After that, E. coli outer membrane with Z domain was laminated on SPR biosensor. In this way, the sensitivity of the sensor can be greatly improved.
Our autodisplay service can provide a simple, fast and cheap way for ELISA to screen anti-specific antibody reactions.
The 60 kDa Ro/SS-A is an antigen that can be found in SLE patients. The Ro/SS-A antigen used for ELISAs screening for human sera against specific antibody is typically recombinantly expressed in E. coli. The whole process is expensive and time-consuming. A more effective method is to express the antigen on the surface of E. coli using autodisplay. Cells displaying 60-kDa Ro/SS-A on the surface are applied as an antigen source demonstrating that autodisplay provides simple, rapid, and cheap access to human antigens for the ELISA screening reaction.
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