Clustering of molecular dynamics trajectories via peak-picking in multidimensional PCA-derived distributions

We describe a robust, fast, and memory-efficient procedure that can cluster millions of structures derived from molecular dynamics simulations. The essence of the method is based on a peakpicking algorithm applied to threeand five-dimensional distributions of the principal components derived from the trajectory and automatically supports both Cartesian and dihedral PCA-based clustering. The density threshold required for identifying isolated peaks (which correspond to discrete clusters) is determined through the application of a variance-explained criterion which allows for a completely automated clustering procedure with no user intervention. In this communication we describe the algorithm and present some of the results obtained from the application of the method as implemented in the molecular dynamics analysis programs carma, grcarma. and cluster5D. We conclude with a discussion of the limitations and possible pitfalls