[2005/04/30] World’s Smallest Rotary Motors Coming Into Focus
World’s Smallest Rotary Motors Coming Into Focus
04/30/2005 Science April 29 had three articles on the ATP
synthase rotary motors that inhabit all living
cells.1,2,3 Using creative techniques of extreme
microscopy and crystallography, research teams are beginning to get more
focused images of the carousel-like rotating engines of both F-type and
V-type motors. (V-type enzymes pump ions into the cell to regulate
acidity. F-type ATP synthase enzymes produce ATP, the energy currency
of the cell.) The rotating rings look like elegant circular
rings of helical units arranged at angles to the axis. From the
side, they look like “concave barrel with a pronounced waist in the
middle, and an inner septum that is probably filled with and electrically
sealed by membrane lipids in vivo.” Scientists are still trying to
figure out how the ions get into the active-site pockets in the subunits
of the ring, and how they create torque to make the carousel go
round. It may result from harnessing Brownian motion in a ratcheting
manner that only allows rotation in one direction. All the
researchers seem surprised that the gear ratio is not an integer, but
rather 10:3 in some species, and 11:3 or 14:3 in others; it may be
necessary that these motors have a non-integer ratio between the bottom
carousel and the top catalytic engine for torque generation and catalytic
activity. They are also beginning to understand the nature of the
camshaft attached to the carousel that induces ATP production in the
top. Whatever their mechanism, these little engines, only 12
nanometers tall, are effective. The review by Junge and Nelson says
these motors can generate an acidity of pH 2 in lemons and 250 millivolts
of electricity in insect guts. We humans also run on
electricity. The constant action of quadrillions of these tiny
generators running day and night in our bodies keeps all our energy
systems humming at
about 116 watts. In another molecular-motor story, Current
Biology4 reported about how actin and myosin work during
cell division to pinch the two daughter cells apart. David R.
Burgess in a review5 states, “Myosin II is the motor for
cytokinesis, an event at the end of cell division during which the animal
cell uses a contractile ring to pinch itself in half. New and
surprising research shows that myosin, either through light chain
phosphorylation or through its ATPase activity, also plays an important
role in both the assembly and disassembly of the actin contractile ring.”
1Wolfgang Junge and Nathan Nelson, “Structural
Biology: Nature’s Rotary Electromotors,” Science
Vol 308, Issue 5722, 642-644 , 29 April 2005, [DOI:
10.1126/science.1112617]. 2Murata et al., “Structure
of the Rotor of the V-Type Na+-ATPase from Enterococcus
hirae,” Science,
Vol 308, Issue 5722, 654-659, 29 April 2005, [DOI:
10.1126/science.1110064]. 3Meier et al., “Structure
of the Rotor Ring of F-Type Na+-ATPase from Ilyobacter
tartaricus,” Science,
Vol 308, Issue 5722, 659-662 , 29 April 2005, [DOI:
10.1126/science.1111199]. 4E. D. Salmon, “Microtubules: A
Ring for the Depolymerization Motor,” Current
Biology, Volume 15, Issue 8, 26 April 2005, Pages R299-R302,
doi:10.1016/j.cub.2005.04.005. 5David R. Burgess,
“Cytokinesis: New roles for myosin,” Current
Biology, Volume 15, Issue 8, 26 April 2005, Pages R310-R311,
doi:10.1016/j.cub.2005.04.008.
None of these five papers mention
evolution once, nor make any attempt to explain how the motors of life
could have arisen by an unguided process of chance or natural law.
Murata’s paper says “Eukaryotic V-ATPases contain 13 different
polypeptides.” Since getting just one usable polypeptide (protein)
is astronomically improbable, it is
utterly out of the question to assume that the complete set of these
specialized functional molecules could have arisen by
chance. Even getting a few of them would be useless; all of
them have to be in the same place, at the same time, in the same
arrangement, together simultaneously for the system to work. ATP
synthase is a classic example of an irreducibly complex system that
defies evolutionary explanation. Since even the simplest organisms
depend on these motors for life, and since Charlie’s magic wand of
natural selection cannot be used at this stage, we have
here a convincing case for intelligent design. Similarly, since
the actin/myosin operation is essential for cell division (e.g.,
replication, an essential prerequisite for natural selection),
evolutionists have only chance as an explanation for the origin of these
exquisite molecular machines. To any thinking person, that would
be absurd. The Kansas school board should hold up the pictures of ATP synthase from these papers and
challenge the Darwinists to explain how such complex systems at the
beginning of life could ever have arisen by chance.
[2005/04/30] World’s Smallest Rotary Motors Coming Into Focus
