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Incredible Kinesin!

Biological ‘robots’ will blow your mind!

by

Published: 26 June 2012 (GMT+10)

Stand and deliver

Kinesin molecules are motor proteins found inside living things. Known as the ‘workhorse of the cell’, they haul vital cargo along roadways in cells called microtubules. Steven Block (professor of applied physics and of biological sciences at Stanford University) has described kinesin this way; "Kinesin functions like a locomotive in cells to ferry cargo back and forth.”1

Illustration by Caleb Salisbury Kinesin

A typical kinesin molecule is a mere 70 billionths of a metre (three-millionths of an inch) long and has an amazing likeness to a person! A typical kinesin has two ‘arms’ on one end (that hold onto the cargo) and two ‘legs’ on the other end that walk along the microtubule, pulling the cargo toward its final destination. In a sense they are like the ‘postman’ delivering mail inside cells.

Biological robots?

Inside all life forms that have nuclei in their cells (eukaryotes), proteins and other parts need to be delivered to specific places within the cell at specific times. If the needed part is a protein, a manufacturing plant (called the ribosome) receives blueprints for the part from the nucleus (the information is stored in the nucleus on a strand of DNA, but the blueprint is sent in the form of an RNA copy of that section of DNA).

This is a complex coordinated effort, as something must first access the creature’s DNA library, unzip it at the exact location needed for the specific information required (for whatever part is to be manufactured), create a duplicate of the information for the part and deliver it to the factory. (See animation, below left.)

Then another organelle in the cell (called the Golgi apparatus) packages the needed part by wrapping it in a bag (called a vesicle) and imprints the ‘address’ where the part is to be delivered in the cell onto the outside of the vesicle ‘parcel’.

Then a kinesin is summoned. It picks up the parcel and ‘walks’ along microtubule roadways in the cell and delivers the parcel where it is needed. (Many different types of kinesin [and kinesin-related proteins] with different specifications and functions have been discovered in various organisms from yeast to humans. The above example was simply an example of a ‘common’ task.)

A view from above

Kinesin is the miniscule longshoreman (stevedore) of the cell, toting parcels of cargo on its shoulders as it steps along a scaffolding of microtubules. Each molecule of ATP fuel that kinesin encounters triggers precisely one 8-nanometer step of the ‘longshoreman’.

To grasp the complexity of what scientists are observing kinesin do, we could use the following hypothetical scenario as an analogy from a more familiar point of view:

Joe is working at his job one day when his machine breaks down. He identifies the broken part and makes a call from his cell phone to a local manufacturer requesting a new one, giving them the part number.

The manufacturer agrees and records Joe’s address. The manufacturer has a list of all the part numbers on hand but not the schematic for them so they send an email to another company (that has a copy of all of the blueprints for every part needed in the industry) requesting the blueprint. A person there makes a photocopy of the needed section and delivers it to the manufacturer.

From the instructions in the blueprints, the factory then manufactures the part and puts it in a package marked with the postal address from its database.

A courier is contacted. He comes to the factory and picks up the package. Having detailed maps of the city, the courier plots out and travels along the most convenient route and delivers the package. Mission accomplished!

Most would agree that the level of complexity just described is pretty impressive. The technology and integrated components (such as the specialized knowledge, communications systems, manufacturing capability, and databases) needed for such intricate procedures are incredibly sophisticated, and all of these steps were coordinated by intelligent people at every stage. However, the actual processes involving kinesin are far more complicated than what ‘Joe’ experienced above.

All in a day’s work

As astounding as this is, research is showing that kinesins do far more than initially thought. Kinesins are now known to support mitosis (cell division) and meiosis (cell division in which a nucleus divides into four daughter nuclei to make reproductive cells). In addition to transport of ‘mundane’ cellular cargo, kinesins transport the neurotransmitters needed for neurons to communicate with one another.

Certain kinesins can dismantle the microtubules after their journey. Controlling the length of microtubules is particularly important during cell division2—lack of control can cause chromosomal instability, which is in turn linked to human cancer.3

Professor Matthias Rief (from the Physics Department of the Munich University of Technology) says, “Our results show that a molecular motor must take on a large number of functions over and above simple transport, if it wants to operate successfully in a cell. It must be possible to switch the motor on and off, and it must be able to accept a load needed at a specific location and hand it over at the destination.”4

123rf.com/Viktor Gmyria

Fast and efficient

Not only do these incredible kinesin robots perform a variety of tasks, they also do so with incredible efficiency! Check out these ‘state of the art’ features:

Power—“Not only is it tiny, but kinesin’s motor is about 50 percent efficient, which is about twice as good as a gasoline engine. And pound for pound, kinesin produces nearly 15 times more power than that man-made engine.”5

Speed—The kinesin motor is impressively fast, capable of 100 steps per second. “Scaled up to our own dimensions, a motor with corresponding properties would travel at similar speeds and produce as much horsepower per unit weight as the jet engines of the Thrust supersonic car6, which recently broke the sound barrier.”7 (This would be proportional to a person moving 600 meters per second or 1,300 miles per hour!)

Energy efficient—Kinesins are powered by the universal energy compound known as ATP (which is produced by another incredible molecular motor called ATP synthase—see animation, below right. Each molecule of ATP “fuel” that kinesin encounters triggers precisely one 8-nanometer step of the ‘postman’, but kinesins go into ‘sleep mode’ when cargo isn’t attached to prevent ATP from being wasted. Similar to how modern computers shut down after a period of un-use to conserve energy, kinesin have a hibernation feature as well. (Although scientists know that the motor folds over in an “autoinhibited” 8 state when resting, the molecular mechanism remains unclear.)

Team players—Kinesin molecules also work together when the going gets tough! If the load needing transport is too heavy for one ‘postman’ to handle, there is “ … significant evidence that cargoes in-vivo are transported by multiple motors.”9

They also demonstrate ‘multiple handling’ of their cargo. Similar to runners in a relay race, kinesins can ‘hand off’ their cargo to a ‘fresh’ bystander after delivering it a certain distance, and the other kinesin will finish the delivery process.

Flexible planning—Kinesins also have a ‘bypass mode’ ability that allows them to navigate around obstructions they may encounter. Similar to a GPS system ‘re-computing’, kinesins have demonstrated the remarkable ability to re-route automatically when needed.

Recycling—The most ardent champion of the ‘green’ movement would be jealous of the kinesin’s conservation and recycling capability. There is good evidence they are either transported back to the cell center in groups by large transport units (like mass transit in cities) or alternatively dismantled and their parts recycled when done their tasks.10

Committed to naturalism

Of course such incredibly sophisticated bio-technology screams “Design”, but does God get the glory in the scientific literature describing these amazing machines and processes? No, ‘nature’ does:

“It is impressive how nature (emphasis mine) manages to combine all of these functions in one molecule. In this respect it is still far superior to all the efforts of modern nanotechnology and serves as a great example to us all.” 11

Why is it that at a time when science is revealing such telling evidence of God’s handiwork that intelligent people can see the evidence and deny the Creator? It’s because of the atheistic, evolutionary indoctrination that most people in the Western world receive, of course. Atheism is committed to naturalism, and so as Dr Scott Todd (an immunologist at Kansas State University) said: “Even if all the data point to an intelligent designer, such an hypothesis is excluded from science because it is not naturalistic”. (This would have been surprising news to the many great God fearing scientists of the past such as Sir Isaac Newton and Louis Pasteur).

Of course, according to evolutionary theory, eukaryote cells supposedly evolved well over two billion years ago12. This means evolutionists are willing to believe that such astoundingly sophisticated technology like molecular motors and their operating systems arose through natural processes (with no intelligence) very early on their imaginary timeline. But this is technology far superior to anything the most intelligent scientific minds on the planet have ever produced!

Is ‘evolution’ the answer to our beginnings?

“Motion at the cellular level is a hallmark of being alive,” Block has said. “A fundamental question is, how did living organisms figure out how to move? The answer is they developed kinesin and several other very efficient protein motors. If kinesin were to fail altogether, you wouldn’t even make it to the embryo stage, because your cells wouldn’t survive. It’s that important.” 13

Evolutionists have no plausible theory on how something as sophisticated as kinesin (and the required operating and communication systems) could have evolved in a gradual fashion (let alone all of the countless other functions and features we know of in so called ‘simple’ living things).

However, when we see similar machines and operating systems (robots, computers, the Internet, etc.) in our everyday life at work or home they are always the result of intelligent and intentional design. How much more logical to believe that the ultimate mind we are able to conceive (the Creator God of the Bible) created all of the marvelous machinery within us and the world around us!

How DNA is transcribed into mRNA with RNA polymerase, then translated into a protein in the ribosome with tRNA ‘adaptor’ molecules. This protein is then escorted by chaperones into a chaperonin so it folds correctly. All this machinery is itself encoded in the DNA, but the DNA can’t be read without this decoding machinery—a vicious circle, or chicken-and-egg problem. Furthermore, most of these processes use energy, supplied by ATP, produced by the motor ATP synthase (right). But the ATP synthase motor can’t be produced without instructions in the DNA, read by decoding machinery using ATP… a three-way circle, or perhaps an egg-nymph-grasshopper problem.

The 20-nanometer motor (height), ATP synthase (one nanometer is one thousand-millionth of a metre). These rotary motors in the membranes of mitochondria (the cell’s power houses) turn in response to proton flow (a positive electric current). Rotation of the motor converts ADP molecules plus phosphate into the cell’s fuel, ATP.

References

  1. Asbury, C.L., Fehr, A.N., Block, S.M., Kinesin Moves by an Asymmetric Hand-Over-Hand Mechanism, news.stanford.edu, accessed September 2010. Return to text.
  2. Peters, C., et al., Insight into the molecular mechanism of the multitasking kinesin-8 motor, nature.com, accessed September 2010. Return to text.
  3. Ref 2. Return to text.
  4. Motor Molecules Use Random Walks To Make Deliveries In Living Cells, sciencedaily. com, accessed July 2009. Return to text.
  5. Leif Bates, K., Molecular Motors-Nature uses tiny nano-machines that could work miracles if we learn how to build them, michigantoday.umich.edu, accessed January 2012. Return to text.
  6. Thrust SSC holds the World Land Speed Record, set on 15 October 1997, when it achieved a speed of 1,228 km/h (763 mph) and became the first car to officially break the sound barrier. Return to text.
  7. Block, S.M., Kinesin: What Gives?, Cell 93:5–8, 1998. Return to text.
  8. Kaan, H.Y.K, et al., The Structure of the Kinesin-1 Motor-Tail Complex Reveals the Mechanism of Autoinhibition, Science 333(6044):883–885, 2011. Return to text.
  9. Erickson R.P, et al., The National Center for Biotechnology Information, Department of Physics and Astronomy, University of California, Irvine, California, USA, May 2011. Return to text.
  10. Gutierrez-Medina, B., et al., Kinesin: an ATPase that steps along microtubules, stanford.edu, accessed January 2012. Return to text.
  11. Ref 5. Return to text.
  12. Marshall, M., Timeline: The evolution of life, newscientist.com, accessed July 2009. Return to text.
  13. Ref 1. Return to text.

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