We are just a very small part of the search space

The theoretical size of the sequence space, i.e. the total number of possible protein sequences is, for all practical purposes, infinite. Assuming that an average protein length is 200 amino acids, there can be 20²⁰⁰ different protein sequences, a number that is much greater than, for example, the number of protons in our Universe.

carte recomandata: Evolutionary dynamics , Martin A. Nowak