The World’s Smallest Motor: more evidence for an Intelligent Designer

By Jon Covey, BA, MT(ASCP)
Edited by Anita Millen, M.D., M.P.H., M.A.

In her review of Darwin’s Black Box by Michael Behe (See Darwin's Black Box), Dr. Millen, described the tiny, amazing motor which powers the flagella of bacteria for movement, only 40 nanometers wide by 60 nanometers high. A nanometer (abbreviated nm) is one billionth of a meter (see drawing). From an evolutionary standpoint, the development of this motor’s components would have conferred no survival value to an evolving bacterium. Natural selection wouldn’t have chosen the genes making up the rotor. The rotor is useless without a stator, drive shaft, and other necessary parts. Making the individual parts would have simply been a burden to the cell, using up its resources and energy, decreasing its ability to compete and survive. Essentially, none of it works or confers survival value until all of it works. This is good evidence of an intelligent designer, not a product of time and chance.

Recently, scientists discovered an even smaller motor 10 nm wide by 8 nm high (See Science News 151:173, 1997 and Nature 386:217-219; 299-302, 1997). This motor is an enzyme named F₁-ATPase, a subunit of ATP synthase. This small motor must rotate so that ATP (adenosine triphosphate–an important energy source for cells) can be made.

According to the Nature articles, when DNA sequence information for the F₁-ATPase became available, the scientists doing the work discovered that it had three catalytic sites made up of three a-subunits, three b-subunits (alternating, making a total of three sites), plus one g-subunit. All three catalytic sites need to interact with the g-subunit to function, otherwise ATP will not be made. This is another example of Behe’s "irreducible complexity." None of it works until all of it works.

In Nature, the reporting scientists wrote:

Cells employ a variety of linear motors, such as myosin, kinesin and RNA polymerase, which move along and exert force on a filamentous structure. But only one rotary motor has been investigated in detail, the bacterial flagellum (a complex of about 100 protein molecules). We now show that a single molecule of F₁-ATPase acts as a rotary motor, the smallest known, by direct observation of its motion. A central rotor of radius ~1 nm, formed by its g-subunit, turns in a stator barrel of radius ~5 nm formed by three a - and three b-subunits.

The researchers attached a fluorescent actin filament to the g-subunit so they could observe its rotation. According to the Science News author, the enzyme puts out a very large torque, comparable to a man rotating a 150-meter rod. The enzyme can spin such a long filament because it automatically ratchets down the rotation rate.

Evolutionists, such as Richard Dawkins, ask us to believe that complex interdependent systems developed entirely by chance over great periods of time. Yet, such things as the complex enzymatic systems within our cells, the blood clotting system, astounding interaction between different parts of our body with our brains and the amazing rotary motors described above strongly argue that a Master Designer was necessary for their creation.