Here are abstracts from two article from the current issue of NATURE
about molecular machines. The table of contents summary says:
"Molecular machines are common in nature, but creating nanoscale devices
from scratch is not as easy it looks. Two ways of making a molecular
motor capable of unidirectional motion have now been demonstrated. In
one system movement is driven by chemical forces, whereas in the other
device rotation is powered by ultraviolet light."
Note the language of intelligent design "creating" and "making"! Also note
that highly intelligent human intelligent designers, with modern technology
find hard to assemble these molecular motors. Yet we are expected to
believe that blind natural forces did it!
As Bill Dembski points out, "The irreducible complexity of such
biochemical systems cannot be explained by the Darwinian mechanism, nor
indeed by any naturalistic evolutionary mechanism proposed to date":
"Perhaps the most compelling evidence for design in biology comes from
biochemistry. In a recent issue of Cell (February 8, 1998), Bruce Alberts,
president of the National Academy of Sciences, remarked, "The entire cell
can be viewed as a factory that contains an elaborate network of
interlocking assembly lines, each of which is composed of large protein
machines....Why do we call the large protein assemblies that underlie cell
function machines? Precisely because, like the machines invented by
humans to deal efficiently with the macroscopic world, these protein
assemblies contain highly coordinated moving parts."...As Behe explains in
Darwin's Black Box, "An irreducibly complex system cannot be
produced...by slight, successive modifications of a precursor system,
because any precursor to an irreducibly complex system that is missing a
part is by definition nonfunctional...Since natural selection can only choose
systems that are already working, then if a biological system cannot be
produced gradually it would have to arise as an integrated unit, in one fell
swoop, for natural selection to have anything to act on."... The irreducible
complexity of such biochemical systems cannot be explained by the
Darwinian mechanism, nor indeed by any naturalistic evolutionary
mechanism proposed to date. Moreover, because irreducible complexity
occurs at the biochemical level, there is no more fundamental level of
biological analysis to which the irreducible complexity of biochemical
systems can be referred, and at which a Darwinian analysis in terms of
selection and mutation can still hope for success. Undergirding
biochemistry is ordinary chemistry and physics, neither of which can
account for biological information. Also, whether a biochemical system is
irreducibly complex is a fully empirical question: Individually knock out
each protein constituting a biochemical system to determine whether
function is lost. If so, we are dealing with an irreducibly complex system.
Experiments of this sort are routine in biology." (Dembski W.A., "Science
and Design", First Things, Vol. 86, October 1998, pp21-27.
http://www.arn.org/ftissues/ft9810/dembski.html).
Steve
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9 September 1999
Nature 401, 150 - 152 (1999) (c) Macmillan Publishers Ltd.
Nanotechnology: Synthetic molecular motors
ANTHONY P. DAVIS
Molecular machines are common in nature, but creating nanoscale devices
from scratch is not as easy it looks. Two ways of making a molecular motor
capable of unidirectional motion have now been demonstrated. In one system
movement is driven by chemical forces, whereas in the other device rotation
is powered by ultraviolet light.
Unidirectional rotary motion in a molecular system
T. ROSS KELLY, HARSHANI DE SILVA & RICHARD A. SILVA
[...]
Light-driven monodirectional molecular rotor
NAGATOSHI KOUMURA, ROBERT W. J. ZIJLSTRA, RICHARD A. VAN
DELDEN, NOBUYUKI HARADA & BEN L. FERINGA
creating nanoscale devices from scratch is not as easy it looks
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http://www.nature.com/server-java/Propub/nature/401152A0.abs_frameset?context=toc
9 September 1999
Nature 401, 152 - 155 (1999) (c) Macmillan Publishers Ltd.
Light-driven monodirectional molecular rotor
NAGATOSHI KOUMURA, ROBERT W. J. ZIJLSTRA, RICHARD A. VAN
DELDEN, NOBUYUKI HARADA & BEN L. FERINGA
Attempts to fabricate mechanical devices on the molecular level have yielded
analogues of rotors, gears, switches, shuttles, turnstiles and ratchets.
Molecular motors, however, have not yet been made, even though they are
common in biological systems. Rotary motion as such has been induced in
interlocked systems and directly visualized for single molecules, but the
controlled conversion of energy into unidirectional rotary motion has remained
difficult to achieve. Here we report repetitive, monodirectional rotation around
a central carbon-carbon double bond in a chiral, helical alkene, with each
360¿ rotation involving four discrete isomerization steps activated by
ultraviolet light or a change in the temperature of the system. We find that
axial chirality and the presence of two chiral centres are essential for the
observed monodirectional behaviour of the molecular motor. Two light-
induced cis-trans isomerizations are each associated with a 180 degrees* rotation
around the carbon-carbon double bond and are each followed by thermally
controlled helicity inversions, which effectively block reverse rotation and thus
ensure that the four individual steps add up to one full rotation in one direction
only. As the energy barriers of the helicity inversion steps can be adjusted by
structural modifications, chiral alkenes based on our system may find use as
basic components for 'molecular machinery' driven by light.
Nature (c) Macmillan Publishers Ltd 1999 Registered No. 785998 England.
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and
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http://www.nature.com/server-java/Propub/nature/401150A0.abs_frameset?context=toc
9 September 1999
Nature 401, 150 - 152 (1999) (c) Macmillan Publishers Ltd.
Unidirectional rotary motion in a molecular system
T. ROSS KELLY, HARSHANI DE SILVA & RICHARD A. SILVA
The conversion of energy into controlled motion plays an important role in
both man-made devices and biological systems. The principles of operation of
conventional motors are well established, but the molecular processes used
by 'biological motors' such as muscle fibres, flagella and cilia to convert
chemical energy into co-ordinated movement remain poorly understood.
Although 'brownian ratchets' are known to permit thermally activated motion in
one direction only, the concept of channelling random thermal energy into
controlled motion has not yet been extended to the molecular level. Here we
describe a molecule that uses chemical energy to activate and bias a
thermally induced isomerization reaction, and thereby achieve unidirectional
intramolecular rotary motion. The motion consists of a 120 degrees* rotation
around a single bond connecting a three-bladed subunit to the bulky remainder
of the molecule, and unidirectional motion is achieved by reversibly introducing a
tether between the two units to energetically favour one of the two possible
rotation directions. Although our system does not achieve continuous and fast
rotation, the design principles that we have used may prove relevant for a
better understanding of biological and synthetic molecular motors producing
unidirectional rotary motion.
Nature (c) Macmillan Publishers Ltd 1999 Registered No. 785998 England.
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* Note: I have replaced the symbol for degrees (as in temperature) with the word
"degrees" because some computers may have trouble receiving it.
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Stephen E. (Steve) Jones ,--_|\ Email: sejones@iinet.net.au
3 Hawker Avenue / Oz \ Web: http://www.iinet.net.au/~sejones
Warwick 6024 -> *_,--\_/ Phone: +61 8 9448 7439
Perth, Western Australia v "Test everything." (1 Thess. 5:21)
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