Export without proteolytic processing of inner and outer membrane proteins encoded by F sex factor tra cistrons in Escherichia coli minicells.

Most tra proteins encoded by the Escherichia coli F sex factor are incorporated into the minicell envelope. We have now assigned the tra proteins to cytoplasm (TraIp and 2b), inner membrane (TraEp, TraMp, and TraSp), and outer membrane (6e, TraAp, TraBp, TraJp, TraKp, TraLp, and TraTp). two proteins, TraDp and 6d, were associated with both inner and outer membranes. The proteins exported to the inner or outer membranes did not undergo proteolytic cleavage (processing) whereas beta-lactamase was processed normally.