Proton Motive Force Drives Flagellar Motility

in this video, we're going to begin our lesson on how the proton motive force drives pro carry, attic, flat gellar motility. And so the proton motive force is commonly abbreviated as just P. M. F. For short. And so the proton motive force, or p. M. F. Is referring to the energy that is generated from the transport of protons or hydrogen ions h plus across the plasma membrane. And so this proton motive force is going to be generated via a series of three steps that we have numbered down below 12 and three, and those numbers correspond with the numbers that we have in the image down below. So keep that in mind as we go through this. And so in the very first step of generating the proton motive force, protons, or hydrogen ions are going to be pumped from the peri plasm into the cell's cytoplasm. And so, if we take a look at our image down below, notice that this is an image of the proton motive force. Again, it's going to involve the movement of protons across the membrane to generate energy. And so notice that this is showing you the structure of a gram negative cells flagellum. And uh you can tell that because notice that there is an outer membrane here which is associated with gram negative cells. And so notice that protons, these H plus ions here that are found in the peri plasm, this region in between the peptidoglycan layer and the cell plasma membrane protons from the peri plasm are going to be transported and pumped into the cell cytoplasm. So you can see that the direction of movement here is uh in this direction right here. And so these protons that are pumped into the cytoplasm are going to interact with charged amino acids on the M. S. Ring protein. And so I recall that protons are positively charged. They are H plus ions. And so they're able to interact electrostatic lee with other charged particles such as amino acids. And so if we take a look at our image down below, notice that in Step two here we're showing you the proton and M. S. Ring interaction, electrostatic interaction. So you can see the protons interacting with the M. S. Ring, which is right here. Yeah. Then the interaction with the M. S. Ring is actually going to cause the fluid gel um to rotate. And of course the rotation of the flagellum is going to lead to either a run or a tumble. Now the actual speed that the protons are pumped into the cell is going to control the rotational speed of the flow gela. And so uh what you can see here is in Step number three we can see how the M. S. The proton M. S. Ring interaction is going to lead to fly gellar rotation and of course rotation of the flu gela is going to lead to movement of the flu gela. Now the energy from the proton motive force or the PMF is going to be used to move the cell towards a more favourable environment where the cell is more likely to be able to survive and thrive. And so this ability for cells to be able to move towards more favorable environment is referred to as chemo taxes, which we're going to talk about in our next lesson video. But for now this year concludes our brief lesson on how the proton motive force drives pro carry attic flat gellar motility. And we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.

Energy generated from a proton motive force (PMF) can be used to power:

• A. Twitching motility
• B. Flagellar rotation
• C. Gliding motility
• D. Conjugation
• E. Flagellar synthesis