Unexpected similarities between raindrops and proteins

Raindrops and proteins seem to have a lot in common. This has been shown in a new study by scientists at Umeå University in Sweden. The principle behind the formation of raindrops is very similar to how proteins fold. This knowledge is vital to our understanding of neurodegenerative diseases like ALS.

These findings have been published in the latest issue of the journal Proceedings of the National Academy of Sciences and have caught the attention of the international research community. The study was carried out by the biochemists Mikael Oliveberg and Linda Hedberg at Umeå University.

To form a raindrop, it is not enough for a few water molecules to stick together. About 100 water molecules have to conglomerate at the same time. If there are fewer, the drop cannot begin to grow, but it falls to pieces immediately.

Using newly developed theory, Linda Hedberg and Mikael Oliveberg have shown that the inscrutable building blocks of the body, proteins, adopt their proper shape in a similar manner. Unlike water, proteins are made up of long chains, and these chains have to instantly fold to a globular form to keep the normal function of the cell. But just like raindrops, it is not enough if just a few segments of the protein chains start tangling together. All parts have to come together at once, otherwise nothing happens. The scientists see a key principle in this.

“Now that we see the similarities between the genesis of raindrops and the folding of proteins we can also analyze protein folding in a clearer light. We have a stringent theory to follow,” says Mikael Oliveberg.

The complicated way in which proteins fold offers the advantage that no half-developed proteins are formed. If such half-developed proteins nevertheless accumulate, they tend to stick to each other, which in turn can lead the cell to “commit suicide”. Such improper folding in the sensitive nerve cells lies behind severe disorders like ALS, mad-cow disease, and Alzheimer’s disease. At present these diseases are incurable because the knowledge of the misfolding process is yet fragmental.

With the aid of the new theory, these scientists are now working to map what parts of the proteins control the folding and what parts are vulnerable to noxious misfolding. The findings could represent an important step toward a more detailed molecular understanding of how proteins behave in our cells and what happens when things go wrong. As so often in the past, parts of the puzzle turn up when they are least expected: in this case the principle behind the formation of raindrops may be the key to understanding neurodegenerative diseases.

“The connection between raindrops and proteins may seem simple, but simple solutions are often the right ones. It also shows how everything fits together in nature. Phenomena recur, but with different faces. If we can understand protein folding with help of this theory, we will also be gaining a greater knowledge of life and why things sometimes go wrong,” says Mikael Oliveberg.