Adaptation of a conjugal transfer system for the export of pathogenic macromolecules

Abstract

Conjugal transfer of bacterial plasmids requires a pore through which DNA can traverse the envelopes of the donor and recipient cells. Recent studies indicate that these pores, which are composed of approximately ten proteins, are evolutionarily related to the transport systems required for the transfer of oncogenic T-DNA from Agrobacterium tumefaciens to plant cells and for toxin secretion from Bordetella pertussis.

Fig. 1

Alignments of the pKM101 pilus cluster genes with the virB operon of Agrobacterium tumefaciens and the ptl region of Bordetella pertussis.

Fig. 2

A model describing the possible localizations of and interactions between 11 IncN plasmid Tra proteins. The colors used match those of Fig. 1.