Classes related to the implementation of the CE alignment algorithm, here called jCE. CE reference:

    Shindyalov IN, Bourne PE (1998)
    Protein structure alignment by incremental combinatorial extension (CE) of the optimal path.
    Protein Eng 11: 739-747

see also:

      Andreas Prlic; Spencer Bliven; Peter W. Rose; Wolfgang F. Bluhm; Chris Bizon; Adam Godzik; Philip E. Bourne (2010)
    Pre-calculated protein structure alignments at the RCSB PDB website
    Bioinformatics 26: 2983-2985