A changing room for proteins! It is a place inside a cell where they can go, fold themselves into their final forms, and come out fully functional. Sounds bizarre? Well, science is full of such amazing surprises.
And, for figuring this one out, Dr. Arthur L. Horwich (Medical geneticist at Yale University) and Dr. Franz-Ulrich Hartl (Max-Planck Institute of Biochemistry, Germany) have won the prestigious Lasker Basic Medical Research Award.
Into the world of proteins
Let’s explore this world of proteins a little more. Proteins are essential to life. They are formed from molecules called amino acids (basically a molecule with the elements hydrogen, carbon, oxygen and nitrogen). These amino acids arrange themselves into 3-dimensional shapes that perform certain functions. These functions include metabolism and allowing medicines (like Tylenol) to help heal the body. This 3-dimensional shape is called a protein.
Different proteins have different strings of amino acids which attract and repel each other in specific ways – this results in particular 3-D shapes for each protein. Under stress or under extreme heat conditions within cells, the proteins become vulnerable and may not end up with the right shape. This would mean that they do not function properly. When proteins don’t function as they are meant to, things go wrong in the body. This is what leads to some types of diseases like Alzheimer’s disease and, in some cases, cancer.
Need help folding?
So, proteins must fold correctly; take their correct shape in space, right? Apparently, to cross mitochondrial membranes, the proteins have to unfold. Well, they have to fold back once done crossing. Now, it turns out, they have help inside the cell to do this!
Horwich and Hartl figured out that there is something called a Heat-Shock Protein 60 (HSP60), a molecule that is shaped like a barrel, which acts like a “changing room.” They called this helper barrel-shaped molecule, the HSP60, a “chaperonin.” Basically, while the sequence of amino acids determines the shape a protein will take, this “chaperonin” is also required to make sure it does.
The protein enters into it, a lid (called a cochaperonin) snaps shut. Inside there, the protein, protected from heat and other molecules, can change into its shape. In 10 seconds, when the lid opens again, the 3-D protein exits. Now, if it is not done changing, it can re-enter the barrel and finish up. Each protein, takes turns doing this until they are done attaining their allotted shapes!
Horwich is not only a scientist, but also works as a medical doctor. He is now investigating if it is possible to make extra copies of the HSP60 so that more proteins have the opportunity to fold correctly. “The hope is that we’ll get better and better at providing something for people who get sick,” he is quoted to have said to the New York Times.
Here is a short video that shows you how protein folds and un-folds, trying to reach its final 3-D shape: Video
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