Tethered proteoliposomes containing human ABC transporter MRP3: new perspectives for biosensor application based on transmembrane proteins.

While transmembrane proteins and transporters comprise one of the largest protein families, their use in biosensors like biochips or lab-on-a-chip devices has so far been limited by their demanding requirements of a stable and compartmentalized lipid environment. A possible remedy lies in the tethering of proteoliposomes containing the reconstituted transmembrane protein to the biosensoric surface. As a proof of concept, we reconstituted the human ABC transporter MRP3 into biotinylated proteoliposomes and tethered those to a gold surface coated with streptavidin on a biotinylated self-assembled thiol monolayer. The tethering process was investigated by quartz crystal microbalance with dissipation monitoring. The final assembly of tethered proteoliposomes exhibited biological activity in terms of drug-stimulated ATP hydrolysis and substrate translocation. The presented facile immobilization approach can be easily extended to other transmembrane proteins as it does not require any modification of the protein and will open up transmembrane proteins for future application in biosensors.