Replica exchange method (REM) is a powerful method for speeding up the sampling of conformational states of proteins with rough energy landscapes, where stable conformational states can be separated by large energy barriers. The usual REM requires that different replicas run synchronously. Serial replica exchange (SREM), a method that is equivalent to standard REM in terms of efficiency, yet runs asynchronously on a distributed network of computers. This unique feature enables it to study the protein folding on the distributed computing environment or even on your desktop at home (for small systems and coarse graining models). SIMTK "Serial_Replica_Exchange" has the feature to do the serial replica exchange. Since it is based on Gromacs-3.1.4, all the tools and functions of Gromacs are still usable. Right now, it is only implemented for the Linux version.