*** For details on how to be removed from this list visit the *** *** CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html *** I find Ca trace of two proteins are similar, but in different N-termal, C-terminal direction, like one from residue id 200 to 300 but another 500 to 400 in same topology. How can I superimpose that, is there any example? Many thanks. Merak Zhang