Evolved sequence features within the intrinsically disordered tail influence FtsZ assembly and bacterial cell division

Megan C. Cohan; Ammon E. Posey; Steven J. Grigsby; Anuradha Mittal; Alex S. Holehouse; Paul J. Buske; Petra A. Levin; Rohit V. Pappu

Our analysis suggests that there is probably an evolutionary selection against FtsZ molecules with low complexity CTT sequences. This selection pressure would appear to protect against lowered cellular stability of FtsZ and tail-mediated interactions that compromise FtsZ assembly. In accord with this proposal, the LZ sequence complexity values of CTT sequences from all 1209 orthologs are higher than those of CTT sequences that engender compromised cellular stability or deleterious tail-mediated interactions ( Figure 6F) . These data lead to the hypothesis that a viable CTT sequence of FtsZ must have a CTL of sufficient amino acid complexity in order to avoid degradation, and an overall κ value to ensure that the tail engages in an optimal balance of intra-and inter-molecular interactions that stabilize the polymer without compromising subunit turnover kinetics or engaging in tail-to-tail associations.