We inserted small light-interacting domains at various locations in the stator complex to see what sites were amenable for labeling and how these affected flagellar rotation and switching. We observe...

Flagellar motility allows bacteria to propel themselves and direct movement according to environmental conditions. It plays a key role in bacterial pathogenicity and survival. We investigated the molecular and structural diversity of the stator motor proteins that provide the ion motive force to power flagellar rotation. This study uses a comparative approach that integrates phylogenetics, 3D protein structure, motility assays, and ancestral state reconstruction (ASR) to provide insights into the structural mechanisms that first powered the flagellar motor. We provide the first phylogenetic and structural characterization and classification of MotAB and relatives.

New analysis shows that the last common ancestor of bacteria had a flagellar motor which enabled it to swim, indicating how important learning to swim was for life.