Interactions between Clostridium difficile and Bacillus subtilis Min systems

In rod-shaped bacteria, the proper placement of division septum at the mid-cell relies on the proteins of the Min system. The main principle of Min system involves formation of inhibitor gradient along the cell axis, whose establishment differs between Gram-negative and Gram-positive bacteria. While in Escherichia coli the Min system undergoes pole-to-pole oscillation, in Bacillus subtilis is the proper spatial inhibition achieved by preferential attraction of the Min proteins to the cell poles [reviewed in 1, 2]. Homologues of both Min systems were found to be present in the genomes of Clostridia, a neighbouring group of Bacilli, including pathogenic Clostridium difficile. Here we investigate interactions of C. difficile Min protein homologues with B. subtilis counterparts and find that many of expected interactions indeed exhibit as positive. Surprisingly, we observe interaction between partners of which one no longer exists as counterpart in C. difficile, indicating a conservation of involved B. subtilis protein. Additionally, we investigate distribution of Min proteins homologues across various Clostridia species.