read coor pdb SGR42_R3Cons_em_bcr3.pdb all rmsd coor heavy 3A-18A,20A-27A,31A-36A,41A-55A ave resOrd_rmsd_heavy rmsd coor backbone 3A-18A,20A-27A,31A-36A,41A-55A ave resOrd_rmsd_bb write best.pdb coor all all pdb quit