At the risk of straying too far off-topic... In biology, there's little difference between "totally unfolded" and "not folded correctly". (In fact, there's bee

At the risk of straying too far off-topic... In biology, there's little difference between "totally unfolded" and "not folded correctly". (In fact, there's been some research indicating that there may not be such a thing as "totally unfolded"; i.e. that all proteins have some structure all the time.) There are two ways that you get proteins improperly folded. The first is that this is how they are made. In bacteria that number is only ~10%, but in eukaryotes (i.e. Humans), that number can be as high as ~50%. These proteins need help from other proteins to fold correctly. The other way you get unfolded proteins is by stress. Usually it's either heat stress or oxidative stress that causes proteins to unfold (not surprisingly, the proteins which help other proteins fold are often called "heat-shock proteins"). As for wether or not "nature has solved this problem", well...of course it has. We're here right? I think the thing to remember is that evolution is not, strictly speaking, an optimization process. Rather, it is a "just good enough" process. For example, a dolphin has more efficient lungs than you, an eagle has better eyes than you, almost everything that walks the earth is faster and stronger than you, and you're actually rather poorly built for walking upright (a reason most of us will suffer lower back pain as we age), but none of that matters. For the niche that humans occupy, their large brains are sufficient to beat out all competitors, and yet chances are that some day something will come around with an even better brain and push us out.