Before revision: Markov state models (MSMs)---or discrete-time master equation models---are a powerful way of understanding the structure and function of proteins and other molecular systems . However, they are typically too complicated to understand.
After revision: Markov state models (MSMs)---or discrete-time master equation models---are a powerful way of understanding the structure and function of molecular systems like proteins. Unfortunately, MSMs with sufficiently many states to make a quantitative connection with experiments (often tens of thousands of states even for small systems) are generally too complicated to understand.