MM-align is designed to structurally align multimeric protein complexes using heuristic iteration of dynamic programming based on TM-score rotation matrix. The multple chains in each complex are first joined, in every possible order, and then simultaneously aligned with cross-chain alignment prevented. The alignment on interface structures can be enhenced by MM-align by an interface-specific weighting factor. A TM-score is reported for assessing the structural similarity of two complexes. References: S. Mukherjee, Y. Zhang, MM-align: a quick algorithm for aligning multiple-chain protein complex structures using iterative dynamic programming. Nucleic Acids Research 2009; 37: e83 Registration not required.