Levinthal's paradox

Levinthal's paradox is a thought experiment in the field of computational protein structure prediction; protein folding is the process by which peptides reach a stable native configuration. In theory, a brute force search, testing all possible conformations, would take longer than the age of the universe to identify this minimum energy configuration (the native state). In reality, protein folding happens very quickly, even for complex structures, suggesting that the intermediate structures are steered to a stable state through an uneven energy landscape.