The millions of proteins in humans and other living things vibrate in different patterns like the strings on a violin or the pipes of an organ, according to a new study in Nature Communications.
Scientists have long suspected that proteins vibrate in such a manner, but now they have the high tech means to prove that this really happens.
The research team, from the University at Buffalo and Hauptman-Woodward Medical Research Institute, found that the vibrations persist in molecules like the "ringing of a bell," lead author and UB physics professor Andrea Markelz said in a press release.
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We are not consciously aware of these non-stop vibrations. (Can you imagine what it would be like if we were?) But it's fascinating to think that a veritable symphony of vibrations plays on in us and in other species.
The tiny motions enable proteins to change shape quickly so they can readily bind to other proteins, a process that is necessary for the body to perform critical biological functions like absorbing oxygen, repairing cells and replicating DNA, Markelz explained.
She added that the research opens the door to a whole new way of studying the basic cellular processes that enable life.
"People have been trying to measure these vibrations in proteins for many, many years, since the 1960s," Markelz said.
She and her team managed to do it based on an interesting characteristic of proteins. They vibrate at the same frequency as the light they absorb. This is analogous to the way wine glasses tremble and shatter when a singer hits exactly the right note.
"Wine glasses vibrate because they are absorbing the energy of sound waves, and the shape of a glass determines what pitches of sound it can absorb," she said. "Similarly, proteins with different structures will absorb and vibrate in response to light of different frequencies."
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In order to study vibrations in a protein known as "lysozyme," the scientists then exposed a sample to light of different frequencies and polarizations, and measured the types of light the protein absorbed. This allowed them to identify which sections of the protein vibrated under normal biological conditions. The researchers were also able to see that the vibrations endured over time, challenging existing assumptions.
"If you tap on a bell, it rings for some time, and with a sound that is specific to the bell," Markelz said. "This is how the proteins behave. Many scientists have previously thought a protein is more like a wet sponge than a bell: If you tap on a wet sponge, you don't get any sustained sound."
She concluded, "The cellular system is just amazing. You can think of a cell as a little machine that does lots of different things - it senses, it makes more of itself, it reads and replicates DNA, and for all of these things to occur, proteins have to vibrate and interact with one another."
(Image: healthy human T-cell; Credit NIAID/NIH)