{
  "id": 6629736,
  "title": "Thermal fractuations assist high-speed rotation of the bacterial flagellar motor at low load",
  "url": "https://urgent.news/2026/09/10/thermal-fractuations-assist-high-speed-rotation-of-the-bacterial",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-10T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.09.750262v1?rss=1"
  },
  "original_language": "en",
  "account": "Bacterial flagellar motors are miniature rotary engines that harness ion flow to produce mechanical motion. These motors rely on proton-coupled rotation of a stator complex, which generates torque. However, the precise mechanism by which this process drives high-speed rotation has remained a mystery. Researchers have now used single-molecule nanophotometry to observe the motor's behavior under low-load conditions. Lowering the cell's pH selectively extended the time the motor spent in each position without altering the duration of each step. This suggests that the dissociation of protons initiates the generation of torque. Further structural analysis indicates that the rotor detaches from the stator before completing a single rotation step, which is approximately 11 degrees in angle. This implies that the power stroke alone is not enough to drive high-speed rotation. Interestingly, the rotational diffusion coefficient of motors without a stator is nearly identical to that of the wild-type motor under low load. This finding supports the idea that intrinsic thermal fluctuations can compensate for the limited reach of the power stroke, allowing the motor to rotate rapidly. The study proposes a hybrid model where ion-driven conformational changes influence random motion, leading to efficient energy transduction.",
  "summary": "The bacterial flagellar motor is a proton-driven rotary nanomachine that converts ion flow into mechanical motion. Proton-coupled rotation of the MotA5-MotB2 stator complex generates torque, yet how this process drives high-speed rotation remains unclear. Here we use single-molecule nanophotometry to resolve stepwise rotation under low-load conditions. Lowering intracellular pH selectively…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}