DNA interacts with Bacillus subtilis mechano-sensitive channels in native membrane patches

Much recent evidence indicates that systems devoted to the transmembrane transport of proteins and/or genetic material in bacteria comprise proteins capable of forming large pores as a key element. In several cases these pores have been observed in electrophysiological experiments after purification and reconstitution of the proteins in artificial bilayers. A comparison of their properties with those of large mechanosensitive channels observed by patch-clamping bacterial proto- or spheroplasts suggests that the latter may be formed by such transport machines. In support of this hypothesis, this paper reports that the properties of high-conductance channels in the membrane of Bacillus subtilis are altered by DNA through specific interactions. Thus, the previously demonstrated interaction between DNA and the same channels reconstituted in planar bilayers, which in that system results in the transmembrane translocation of the genetic material, takes place also in the native membrane.