system
Given the following post, respond as if you're commenting on Reddit:
human
What causes Amino Acids to "fold" into proteins?
gpt
The amino acid sequence of a protein is going to ultimately determine how it is going to fold, and the folding is stabilized by several factors.  The biggest factor driving protein folding is hydrophobic interactions. 

If you're unfamiliar with this, its basically the same idea as when you add oil to water, they dont mix and the oil will move together.  This is because although the entropy of the oil is going to be decreased by being near each other, the overall entropy of the system is increased by the water molecules being moved away form the hydrophobic oil. 

This same principle drives the folding of proteins.  There are several amino acids that have big bulky hydrophobic groups that water wants to push away from and forces themselves to be near each other.  Once folded the protein's folded form is further stabilized by other interactions such as di-sulfide bonds, electrostatic interactions between polar side chain groups, hydrogen bonds, and van der waals interactions.