Bell-Ringer: Protein Vibrations Optimized for Interaction
It was Erwin Schr�dinger who first suggested that proteins might vibrate. Now, scientists at the University of Glasgow have given his idea a ringing endorsement. This is a story of how quantum mechanics has conspired with biological design to optimize living processes. Sound like design? It rings a bell, for sure.
And what a vibration it is! Incredibly fast, the physicists say:
Using modern laser spectroscopy, the scientists have been able to measure the vibrational spectrum of the enzyme lysozyme, a protein that fights off bacteria. They discovered that this enzyme rings like a bell with a frequency of a few terahertz or a million-million hertz. Most remarkably, the ringing involves the entire protein, meaning the ringing motion could be responsible for the transfer of energy across proteins. (Emphasis added.)
What's amazing about this ultra-high-pitched ring is that it lasts only long enough to allow the protein to interact with other proteins. Here's another case of Goldilocks fine-tuning:
The experiments show that the ringing motion lasts for only a picosecond or one millionth of a millionth of a second. Biochemical reactions take place on a picosecond timescale and the scientists believe that evolution has optimised enzymes to ring for just the right amount of time. Any shorter, and biochemical reactions would become inefficient as energy is drained from the system too quickly. Any longer and the enzyme would simple oscillate forever: react, unreact, react, unreact, etc. The picosecond ringing time is just perfect for the most efficient reaction.
Yes, isn't evolution wonderful. Once again, it has optimized something that had to be optimized before life began -- all by unplanned, undirected, natural forces that knew nothing about optimization.
These tiny motions enable proteins to morph quickly so they can readily bind with other molecules, a process that is necessary for life to perform critical biological functions like absorbing oxygen and repairing cells.
One of the researchers, a specialist in chemical physics, called it "highly unexpected" to find that proteins have mechanical properties that are "geared for maximum efficiency." Now that he knows, he believes they might be able to discover "whether these mechanical properties can be used to understand the function of complex living systems." Yes indeed. Why are we not surprised?
Their eminent predecessor at the University of Glasgow, the great physicist Lord Kelvin, would not have been surprised, either.
"But overwhelmingly strong proofs of intelligent and benevolent design lie all around us," he said in 1871, "and if ever perplexities, whether metaphysical or scientific, turn us away from them for a time, they come back upon us with irresistible force, showing to us through nature the influence of a free will, and teaching us that all living beings depend on one ever-acting Creator and Ruler."