September 5, 2022 | David F. Coppedge

Molecular Machines Labor 24×7 Every Day

It’s Labor Day in America, but the molecular motors
in your body never take a holiday break.

 

 

Scientists in Germany took over ten million images of a little motor in cells called RuvAB. It allowed them to produce a short animation of this machine at work. Watch it in this press release from the Helmholtz Association released August 29th. Any overture would be superfluous.

Impressions? The scientists were amazed.

The press release illustrates a Holliday Junction in DNA with the motors portrayed as gears. Credit: CSSB, Nicola Graf

Speaking of holidays, this apparatus works on “Holliday junctions” that form during genetic recombination. You can read about those at Britannica. The machine can’t take a holiday, though, or life would stop.

If you want more details about this biological wonder, see their open-access paper in Nature and look through the figures.

This machine belongs to a class of molecular motors called AAA+ ATPases. Many of them have a rotary mode of action. For more on this class of molecular machines, see this paper in Current Opinion in Structural Biology from February 2021.*

A few points are worth noting:

  • The animation is in slo-mo. The scientists say that the motor’s operations “are very fast and highly dynamic.
  • As you can see, the machine is composed of multiple moving parts that operate in a precision sequence.
  • The authors say that mutational studies broke the machine.
  • The authors never explain how such a biological wonder could have evolved.
  • We have similar machines in our bodies, but this example was found in… (get ready…) bacteria.
  • The motors are essential for genome integrity. A bacterium without operations like this would quickly go extinct.

Need we say more?

Frame from animation of RuvAB driven DNA branch migration at the Holliday junction. Animation: CSSB, Jiri Wald.

We hold these truths to be self-evident: life did not evolve. It was designed.

 

*That paper struggles to explain how these motors could have evolved. They can’t even classify them as related by evolutionary ancestry:”the original classification of AAA+ ATPases based on structural PS1i, H2i and PS2i insertions and assuming their emergence only once in the course of the superfamily evolution may be outdated,” they say. “The evolutionary history of the AAA+ superfamily may be more complex, suggesting that a fresh look at the classification system based on large-scale analysis is needed in light of the ever-growing structural information.” They call this one, RuvB, “an evolutionarily distinct member of Clade 5.” Did it just pop into existence? How foolish is that supposition?

In the end, they cannot find a scheme of evolutionary origin or common ancestry, and call for “further intensive research” to figure it out (i.e., futureware).

 

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