I believe that the reason why proteins fold in polynomial time (not necessarily linear) is that nature's proteins are "easy" to fabricate. To use the TSP as an

I believe that the reason why proteins fold in polynomial time (not necessarily linear) is that nature's proteins are "easy" to fabricate. To use the TSP as an analogy, think of a protein as a configuration of cities. The proteins in our body are the solutions of the easy configurations, i.e. a group of cities arranged in a circle. Nature hasn't been able to find the really hard solutions. We would like to explore the full configuration space, to look for new proteins, and that's still hard. Or maybe I misunderstand.