Hi, All, I have a question about rmsd calculation. I have some pdbs (100 residues ) and these pdbs differ pretty much only the loop region 40-60. Is there any easy way that I can superimpose the fixed region ( 1-40,60-100) and then calculate the rmsd for the loop?I need to calculate for each pair, so if there is any script or program available to do this quickly, that would be great. Thanks. Jenny