FTA: The same explosion of combinatorial options happens for proteins, which are molecules made up of many tens to hundreds of amino acids bound together in chains and folded up into particular molecular shapes. There are 20 different amino acids found in natural proteins, and for proteins just 100 amino acids long (which are small ones) the number of permutations is 10130. Yet the 4 billion years of evolution so far have provided only enough time to create around 1050 different proteins. So how on earth has it managed to find ones that work?