Reconstitution of peptide-binding activity by TAP in proteoliposomes

The purification and functional reconstitution of the transporter associated with antigen processing (TAP) is crucial for a complete molecular understanding of its action. Here, we report the conditions for the successful solubilization of human TAP from cellular membranes while maintaining TAP peptide-binding activity. In addition, solubilized TAP was incorporated into proteoliposomes and shown to possess specific peptide-binding activity. These studies provide the foundation for future attempts to achieve the complete functional reconstitution of TAP, which includes peptide transport.