Previous work showed that SecA alone can promote protein translocation and ion-channel activity in liposomes, and that SecYEG increases efficiency as well as signal peptide specificity. We now report that SecDF.YajC further increases translocation and ion-channel activity. These activities of reconstituted SecA-SecYEG-SecDF.YajC-liposome are almost the same as those of native membranes, indicating the transformation of reconstituted functional high-affinity protein-conducting channels from the low-affinity SecA-channels. Published by Elsevier Inc.