Over at A Man with a Ph.D., Richard Gayle thinks that work done at my Alma Mater by Devens Gust and others will have a greater impact than Craig Venter's frankenstein bid. In terms of technology, this is almost certainly true, but you've got to admit, creating an organism from chemicals in bottles is an amazing feat. But harnessing photosynthesis would certainly provide for technological advancements far beyond the simple inorganic processes we rely on today.
This interesting looking molecule is called a triad because it is made of three smaller molecules stuck together. It is one of several artificial biomolecules manufactured in Dr. Gust's laboratory at ASU. The long worm looking part on the right is a conjugated hydrocarbon chain about 25 carbon atoms long. Called a carotenoid polyene, this part acts as a wire, because alternating double and single bonds make up a molecular orbital that is as long as the carotenoid molecule. That type of molecular orbital (called a conjugated pi bond) can conduct electrons at nearly the speed of light.
| You may remember molecular orbitals from the piece on halogen spectroscopy. Molecular orbitals form wherever electrons from atoms overlap when the atoms are bonded together in molecules. There are many more energy levels to molecular orbitals than in the original atomic orbitals. You can see this in the vertical bands of light and dark lines in the bromine and iodine spectra.
If nodes, that is the beginings and ends, of the molecular orbitals line up just right, the molecular orbital will conduct electrons. A conjugated system of pi bonds is just such a set of molecular orbitals. It is carbon's ability to form pi bonded and conjugated molecules that make it the ideal element to build such complex systems as living entities. |
The "wire" molecule is attached to a porphyrin ring (a twenty carbon conjugated outer ring with a four nitrogen inner ring.) This part is similar to the structure of natural chlorofil in plants or hemaglobin in blood and it works like a capacitor: the inner nitrogen atoms have electrons that can be easily moved because they are in unbonded atomic orbitals of the nitrogen atoms. When those electrons are moved away from the center of the ring, the entire ring becomes positivly charged as the electrons from the outer ring surge in to take their place.
So far this structure looks like a very simple biomolecule. But on the opposite side of the porphyrin ring from the carotenoid chain is an entirely non-biological structure: a "Bucky Ball", also known as C-60 fullerene. 
Both names mention Buckminster Fuller, because the molecule is a tiny sphere made entirely of carbon atoms, each (pi) bonded to three other carbon atoms, like Fuller's invention, the geodesic dome. Like any conductive sphere, the fullerene can take extra electrons and 'spread them around' so the charge will stay on the sphere. This effect is familiar if you've ever rubbed a balloon on your shirt to make it stick to a wall.
Now you can see that this molecule will separate positive and negative charges, but what moves the electron out of the inner porphyrin ring in the first place? A beam of light - actually a single photon energizes the electron on one of the inner nitrogens and it jumps out of the ring and sticks to the sphere like a balloon to the wall. As the electrons surge in to the ring to neutralize the charge, the positive charge runs down the "wire" and the molecule becomes relatively stable with a positive end (the tip of the carotenoid 'wire') and a negative end (the fullerene ball.) 
Dr. Gust says that this molecule "stores a considerable fraction of the light energy as electrochemical potential energy." He believes these molecules lead the way toward bioelectronic devices.
Imagine now, if you will, a vat in a lab with huge (on a molecular scale) scorpion like molecules crawl around in nucleic and amino acids building genetic and cellular materials, until finally constructing a bioelectronic brain. Talk about Abbey Normal!
