SEGMER is a segmental threading algorithm designed to recoginzing substructure motifs from the Protein Data Bank (PDB) library. It first splits target sequences into segments which consists of 2-4 consecutive or non-consecutive secondary structure elements (alpha-helix, beta-strand). The sequence segments are then threaded through the PDB to identify conserved substructures. It often identifies better conserved structure motifs than the whole-chain threading methods, especially when there is no similar global fold existing in the PDB. References: S. Wu, Y. Zhang. SEGMER:identifying protein sub-structural similarity by segmental threading. Structure, vol 18, 858-867 (2010). Registration not required.