When talking of motors, most individuals consider these powering automobiles and human equipment. Nonetheless, organic motors have existed for thousands and thousands of years in microorganisms. Amongst these, many bacterial species have tail-like constructions — referred to as flagella — that spin round to propel themselves in fluids. These actions make use of protein complexes generally known as the “flagellar motor.”
This flagellar motor consists of two fundamental elements: the rotor and the stators. The rotor is a big rotating construction, anchored to the cell membrane, that turns the flagellum. However, the stators are smaller constructions that include “ion pathways,” which may match protons or sodium ions relying on the species. As charged particles undergo a stator, it undergoes structural modifications that push in opposition to the rotor, inflicting it to spin. Though many research have targeted on the stators, the exact construction and mechanisms of the ion pathways stay elusive.
Towards this backdrop, a analysis group led by Assistant Professor Tatsuro Nishikino from Nagoya Institute of Expertise analyzed the flagellar motor within the bacterial species Vibrio alginolyticus. Different members of the group included Norihiro Takekawa and Katsumi Imada from Osaka College, Jun-ichi Kishikawa from Kyoto Institute of Expertise, and Seiji Kojima from Nagoya College. Their findings have been printed in Proceedings of the Nationwide Academy of Sciences on December 30, 2024.
The researchers employed cryo-electron microscopy (CryoEM), a strong method that captures high-resolution photos of biomolecules by quickly freezing them and imaging them with an electron microscope. Utilizing CryoEM on regular and genetically modified V. alginolyticus, the group took snapshots of stator complexes in several states and recognized key molecular cavities for sodium ions.
Based mostly on the outcomes, the group proposed a mannequin describing how sodium ions stream via the stator. Briefly put, the subunits that kind the stators in Vibrio alginolyticus, organized in a hoop, act as size-based filters that enable the consumption of sodium ions — however not different ions — into the recognized cavities. The researchers additionally decided the mechanisms by which phenamil, an ion-channel blocker, inhibits the stream of sodium ions via the stator.
The findings of this research may have essential medical implications. “Flagellar-based motion is concerned in infections and toxicity of some species of pathogenic micro organism. One motivation behind this research was discovering methods of inactivating such micro organism by proscribing their motion. Thus, understanding the molecular mechanism of flagellar motility will probably be key for attaining this,” remarks Tatsuro.
Furthermore, data of flagellar motors may result in modern designs for microscopic machines. “Flagellar motors are molecular nanomachines with a diameter of roughly 45 nm and an vitality conversion effectivity of roughly 100%. Our findings are a giant step to make clear their torque-generation mechanisms, which might be important for the engineering of nanoscale molecular motors,” concludes Tatsuro.
