Install libssm1 by entering the following commands in the terminal:
sudo apt update sudo apt install libssm1
macromolecular superposition library - runtime
SSM is a macromolecular coordinate superposition library, written by Eugene Krissinel of the EBI. . The library implements the SSM algorithm of protein structure comparison in three dimensions, which includes an original procedure of matching graphs built on the protein's secondary-structure elements, followed by an iterative three-dimensional alignment of protein backbone Calpha atoms. . The algorithm implemented by the software is described in: E. Krissinel & K. Henrick (2004) Secondary-structure matching (SSM), a new tool for fast protein structure alignment in three dimensions. Acta Crystallogr D Biol Crystallogr. 60, 2256-68. . This package contains the shared library components needed for programs that have been compiled with the ssm library.