- The protein folding process is the process in which polypeptides fold into a functional three-dimensional structure from a random coil
- Each protein is initially an unfolded strand of amino acids. The polypeptide lacks any sort of structure until the amino acids react with each other to form a specific three-dimensional structure
- The specific amino acid sequence determines what role within the body the protein will play. The protein initially looks like a loose string lying on the ground undone but once folded it looks similar to a coiled spring
- When proteins fail to hold their structure the protein becomes inactive. It is believed that many diseases are a result of an accumulation of incorrect protein folding
The amino acid structure defines its primary role within the body. The proteins fold themselves spontaneously but the process is also dependent upon the right conditions within the body such as solvency, the concentration of salts and the activity of molecular chaperones. During protein folding the core is stabilized by side chain packing. This minimizes the number of side chains being exposed to the water, which is an important function of protein folding. Intramolecular hydrogen bonds form providing an important contribution of protein stability. The strength of the hydrogen bonds also depend on their environment. So the h-bonds that are formed in a hydrophobic core are more effective than h-bonds that are exposed to the watery environment.
Special proteins called chaperones also play an important role during protein folding. Many proteins are able to fold unassisted but when the environment is crowded the chaperones prevent misfolding. The essential function of folding is that the amino acid sequence of each protein is embedded with specific information regarding the native structure and the path to that state.
In some conditions proteins will not fold into their correct forms. Temperatures that are too high or low cause unstable proteins to unfold and denature. Extreme ph levels, and chemical toxins can cause the same unfolding process as well. Denatured proteins are linked with many illnesses such as mad cow disease, Alzheimer’s, Huntington’s, and Parkinson’s disease. It is not fully know what is behind the dysfunction of the protein. Protein replacement therapy has been the traditional mode of treatment with new treatments such as pharmaceutical chaperone therapy becoming more popular.
The folding process varies greatly from protein to protein. Outside the cell, the slowest folding proteins may require several minutes to hours to fold into their proper state. They pass through several intermediary states along the way that serve as checkpoints to completion. Very small single-domain proteins typically fold in one single step. It usually takes mere milliseconds to complete the folding process.
As you can see, the folding of proteins is a very complex biological journey that works best in a healthy environment. With a deeper understanding of the role of protein and amino acids you should be even more aware of the importance of a healthy body. As more research is done on the subject it is the hopes that advanced therapies and cures will become a reality.
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