Without proteins nothing in our body would happen. For almost everything in our body depends on proteins, from respiration to cell division. The molecular motors responsible for cell division or carrying cargo from one part of a cell to another, to the very glue that holds tissue together. Lets just say proteins are the engines of our existence.
Proteins consist of polymer chains folded into intricate three dimensional structures. If they arent folded absolutley perfectly, then they wont work properly. Moreover every molecule of the same protein folds into exactly the same conformation! Pretty remarkable.
Protein structure reminds me of one of my favourite childhood characters, Mr Messy
What a protein does when it folds is it explores lots and lots of possible conformations. The laws of thermodynamics mean that it will adapt the lowest possible energy state, which happens to be the highest entropy state. The final state is dictated by the sequence of amino acids in each chain, which in turn affect interactions between other chains and the solvent the protein resides in.
One of the proteins I've been working on is the enzyme nitric oxide synthase, see below. At first inspection it looks pretty messy. But not everything is what it seems...