Path-planning algorithm for transportation of molecules through protein tunnel bottlenecks

We present a simple and fast path planning algorithm for transportation of a set of tightly connected sphere objects (a small molecule) through a narrow gap. In our approach we are using common sampling-based path planning, however, instead of sampling the entire configuration space, we estimate which subsets of this space must be crossed on the desired path. In comparison with other methods using minimal bounding volumes, we improve the algorithm accuracy for arbitrary shaped molecules and significantly reduce the number of generated samples as well as time cost of path planning. We have accomplished a number of tests on scenes formed by proteins and ligand molecules. The results suggest that the proposed method works well in practice and the number of generated samples is substantially lower then the proved upper bound.