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

A large number of distinct conformations might be compatible with similar values of R g and δ * . Here, we refer to this feature as the ruggedness of the energy landscape. Following previous approaches , we quantify ruggedness in terms of the degree of similarity / dissimilarity of backbone dihedral angles among every pair of conformations sampled by each variant. This yields a distribution of similarity / dissimilarity values denoted as p(D) and we take the mean value, denoted as D to be an average measure of backbone dihedral angle similarity / dissimilarity. For a well-folded protein, such as the FtsZ core, the value of D will be small because the backbone dihedral angles of distinct conformations that are accessible as a result of spontaneous fluctuations will be similar to one another. In contrast, the value of D will be higher for systems that sample conformations with distinctly different patterns of backbone dihedral angles.