RECONSTITUTION OF FHUA, AN ESCHERICHIA-COLI OUTER-MEMBRANE PROTEIN, INTO LIPOSOMES - BINDING OF PHAGE T5 TO FHUA TRIGGERS THE TRANSFER OF DNA INTO THE PROTEOLIPOSOMES

The Escherichia coli outer membrane protein FhuA catalyzes the transpo rt of ferrichrome and is the receptor of bacteriophage T5. Purified Fh uA was reconstituted into liposomes. The size of the proteoliposomes a nd the distribution of the proteins in the vesicles were determined by freeze fracture electron microscopy. Unilamellar vesicles with a diam eter larger than 200 nm were observed frequently. FhuA was symetricall y oriented in the proteoliposomes. Reconstituted FhuA was functional a s binding of phage T5 induced the release of phage DNA and its transfe r inside the vesicles.