The 2016 Nobel Prize in Chemistry was awarded to three scientists who built simple “nano” machines out of individual molecules. I think the stark contrast between those and the sophisticated machinery found in living cells points strongly to the purposeful design of life.
One of the Laureates, Fraser Stoddart of Northwestern University, started the field of artificial molecular machines in 1991 when his laboratory synthesized a barbell-shaped molecule with a separate ring around the bar. To do so they first carefully constructed a rod-shaped molecule that could electrically attract a laboriously-made, ring-shaped molecule, threading the ring on the rod. They then chemically attached bigger molecules onto both ends of the rod, trapping the ring on it. The group showed that, when heated, the ring could move from one end of the rod to the other.
Over the decades the Northwestern group and other clever chemists designed additional molecular machines. Stoddardt added electrically charged chemical groups near the ends of his barbell molecule that could be changed by altering the acidity of the environment, allowing the investigator to control which end of the rod attracted the ring. In the right circumstances, that might be able to act as a molecular switch. Another of the three Nobel prize winners developed a molecular motor. Using clever tricks the chemist connected two paddle-shaped molecules in such a way that they could rotate in only one direction (not in random directions as is typical of molecules). Later his group attached four such motors to a molecular chassis and axles to make a “nanocar” that could travel atomic distances when nudged by a special microscope.
Articles reporting on the Prize were filled with praise for the ingenuity of the scientists. Yet there was also an undertone of skepticism about the whole project. One German chemist foresaw looming technical difficulties, “I’ve always been a bit skeptical of artificial motors. They’re too difficult to make, too difficult to scale up.” An overview article remarked that “Some chemists argue that although these motors are cute, they are ultimately useless by themselves.” So far the nanomachinery hasn’t been put to any practical use, but advocates are sure that will change. Commented one scientist who helped organize a recent meeting on nanomachines, “We need to convince [technical businesses] that these molecules are really exciting.”
Many of the pioneers of the field drew inspiration from molecular machines discovered in biology such as the bacterial flagellum, a whip-like outboard motor that can propel bacteria through liquid. Yet the molecular machines laboriously constructed by our brightest scientists are Tinkertoys compared to the nanotechnology found in living cells. That may change — with the expenditure of much effort and brain power the chemists’ machines may be improved in the future. But right at this very moment sophisticated molecular robot walkers à la Star Wars are transporting critical supplies from one part of your cells to others along molecular highways, guided by information posted on molecular signposts. Molecular solar panels that put our best technology to shame are found in every leaf. Molecular computer control systems run the whole show with a reliability that exceeds that of, say, a nuclear reactor. What’s more, unlike the artificial molecular machines that were painstakingly assembled by chemists, cellular molecular machines assemble themselves. As an astonished science writer once put it: “The cell’s macromolecular machines contain dozens or even hundreds of components. But unlike man-made machines, which are built on assembly lines, these cellular machines assemble spontaneously from their protein and nucleic-acid components. It is as though cars could be manufactured by merely tumbling their parts onto the factory floor.” Now those are smart materials!
Here’s a question that’ll get you into trouble in a lot of places for asking it out loud: if brilliant scientists can manage to make only toy molecular machines, what does it take to make the sophisticated machinery of the cell? For the past several decades I and others have been arguing that the ultra-sophisticated systems at the foundation of life powerfully bespeak purposeful design — and for the same reason that the much simpler machines made by Nobel prize winners do: it takes intelligence and planning to arrange multiple parts into a working machine.
Critics retort that, given billions of years and the whole world to work with, Darwin’s mechanism of random mutation and natural selection could do the job. But there’s no good reason to think so. The best, most recent laboratory and field evolution experiments show that random mutation most often breaks or damages genes that already exist and, counterintuitively, that sometimes helps a species survive. Needless to say, a process which most often breaks genes isn’t going to build much of anything. Another common objection I hear is that the conclusion that the molecular foundation of life was purposely designed has religious implications. But so what? Science is supposed to be a search for truth based on our best understanding of nature. Science isn’t supposed to shy away from a conclusion just because it doesn’t fit some people’s philosophical preconceptions.
Perhaps the awarding of the 2016 Nobel Prize in Chemistry for the intelligent design of simple molecular machines will help some people realize that purposeful design is also a compelling explanation for the sophisticated machinery of the cell.
Michael J. Behe is the author of “Darwin’s Black Box: The Biochemical Challenge to Evolution” and the topic of a new film, Revolutionary: Michael Behe and the Mystery of Molecular Machines at www.revolutionarybehe.com.