`  :::::::: Yes, authors of the paper cited in conformational entropy article assumed that backbone and side-chain entropies are uncoupled. That was a valid approximation in their case, since the backbone was fixed. But the equation in  conformational entropy article is simply a general definition of entropy (not necessarily conformational). Note that p(i) can be a probaility of any state of any system. I am not familiar with any publications that would say this equation is ``problematic``. The problematic can be only definition of states, which is often indeed the case.  `