Biochemical characterization and visualization of plasma membrane-DNA-protein complexes from Bacillus subtilis.

Subcellular fractions containing plasma membranes with bound DNA and associated proteins were isolated from two different cultures of Bacillus subtilis 168 growing exponentially at different rates. Differences in the contents of individual between the dissociated complexes, established electrophoretically, can be explained by dynamic binding of the proteins to DNA, resulting in a control of DNA, resulting in a control of DNA replication. Electron microphotographs of isolated complexes display, in addition to unit membranes, associated filamentous structures in different arragement. Patterns obtained after treating the complexes with nucleases suggest a polydeoxyribonucleotide character of the filamentous structures.