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Invisibleelbisivni
Registered: 10/01/06
Posts: 2,839
Microscopic 'Clutch' Puts Flagellum In Neutral
    #8554393 - 06/23/08 01:05 PM (15 years, 10 months ago)

I thought this was pretty neat..



Quote:

A tiny but powerful engine that propels the bacterium Bacillus subtilis through liquids is disengaged from the corkscrew-like flagellum by a protein clutch, Indiana University Bloomington and Harvard University scientists have learned. Their report appears in Science on June 20.

Scientists have long known what drives the flagellum to spin, but what causes the flagellum to stop spinning -- temporarily or permanently -- was unknown.

"We think it's pretty cool that evolving bacteria and human engineers arrived at a similar solution to the same problem," said IU Bloomington biologist Daniel Kearns, who led the project. "How do you temporarily stop a motor once it gets going?"

...

EpsE is thought to "sit down," as Kearns describes it, on the flagellum's rotor, a donut-shaped structure at the base of the flagellum. EpsE's interaction with a rotor protein called FliG causes a shape change in the rotor that disengages it from the flagellum's proton-powered engine.

more: http://www.sciencedaily.com/releases/2008/06/080619142109.htm




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From dust you are made and to dust you shall return.

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InvisibleDieCommie


Registered: 12/11/03
Posts: 29,258
Re: Microscopic 'Clutch' Puts Flagellum In Neutral [Re: elbisivni]
    #8556386 - 06/23/08 10:13 PM (15 years, 10 months ago)

That is neat.  The flagellum is amazing.  I wonder if any other animals have such rotary motion?

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Invisiblejohnm214
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Registered: 05/31/07
Posts: 17,582
Loc: Americas
Re: Microscopic 'Clutch' Puts Flagellum In Neutral [Re: DieCommie]
    #8557142 - 06/24/08 03:24 AM (15 years, 10 months ago)

I don't get it.. what's the point of a clutch?  Are the tiny proteins of such high inertia they can't stop spinning? Why not just stop the engine?  Do protein engines stall?

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Invisiblejohnm214
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Registered: 05/31/07
Posts: 17,582
Loc: Americas
Re: Microscopic 'Clutch' Puts Flagellum In Neutral [Re: johnm214]
    #8557174 - 06/24/08 03:55 AM (15 years, 10 months ago)

I can't get this article

What I imagine is going on is that the protein is more akin to the ignition or gas shut off switch than the clutch on a car.

If the mechanism, which I'm not educated on- someone help me out if they know something bout this- is similar to how skeletal muscle contracts, then I think the "clutch" is really more of a gas shut off valve or an ignition key.  With muscle, the mysoin will constantly work, it takes the troponin to actually block the myosin from working, physically, for it to stop- or the system can run out of ATP.

Likewise in this case, if the mecahnism will constantly spin without input from the nervous system, they must physically seperate/block the proteins to have them stop their actions.

In this way, I'd imagine the "clutch" they've labled would really be closer to an ignition switch, or something that actually stops the pistons from moving- not a clutch.

The clutch has nothing to do with the operation of the engine and the production of energy, while the ignitiion switch does- it stops the engine from operating... so if the flagella work like muscle, I think their analogy is poor.

I guess really their is no suitable analogy in a car though, you'd need something that physically removes the pistons from the car or something- that would seem to be an accurate analogy.


Course I could just be wrong, and I'm not confident as to how flagella work.

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InvisibleDieCommie


Registered: 12/11/03
Posts: 29,258
Re: Microscopic 'Clutch' Puts Flagellum In Neutral [Re: johnm214]
    #8557557 - 06/24/08 08:38 AM (15 years, 10 months ago)

What I get from it is, it is like a clutch in the fact that the 'proton engine' keeps moving.  The clutch mechanism engages and disengages the flagellum from the moving 'proton engine'.

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InvisibleTaharka
The Root of the Problem
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Registered: 09/29/05
Posts: 686
Re: Microscopic 'Clutch' Puts Flagellum In Neutral [Re: johnm214]
    #8561809 - 06/25/08 09:55 AM (15 years, 10 months ago)

The flagellum is driven by a proton pump - think of it like a turbine that is driven by the flow of protons across the membrane, instead of water. So this "clutch" protein disengages the flagellum from the spinning part of the turbine.

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InvisibleDieCommie


Registered: 12/11/03
Posts: 29,258
Re: Microscopic 'Clutch' Puts Flagellum In Neutral [Re: Taharka]
    #8562816 - 06/25/08 02:06 PM (15 years, 10 months ago)

The protons are always being pumped then right?  They dont turn off and on?

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