Single-Molecule Dynamics of DNA Receptor ComEA, Membrane Permease ComEC, and Taken-Up DNA in Competent Bacillus subtilis Cells
Marie Burghard‐Schrod, Alexandra Kilb, Kai Krämer, Peter L. Graumann
Abstract
Bacteria can take up DNA from the environment and incorporate it into their chromosome, which is termed "natural competence" that can result in the uptake of novel genetic information. We show that fluorescently labeled DNA moves within the periplasm of competent Bacillus subtilis cells, with similar dynamics as DNA receptor ComEA. This finding indicates that DNA can accumulate in the periplasm, likely bound by ComEA, and thus can be stored before uptake at the cell pole, via integral membrane DNA permease ComEC. Assembly of ComEC at the cell pole likely occurs by a diffusion-capture mechanism. DNA uptake into cells thus takes a detour through the entire periplasm and involves a high degree of free diffusion along and within the cell membrane.