Dear:
  I am trying to refine my model with loop refine protocol. But it is always said:
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  File "/usr/lib64/python2.4/site-packages/modeller/coordinates.py", line 226, in __getitem__
    (self.offset, self.length, self.suffix))
  File "/usr/lib64/python2.4/site-packages/modeller/util/modutil.py", line 19, in handle_seq_indx
    int_indx = lookup_func(*args)
  File "/usr/lib64/python2.4/site-packages/modeller/coordinates.py", line 289, in _indxres
    raise KeyError("No such residue: %s" % indx)
KeyError: 'No such residue: 273:'



Here is my script, could you please give me some advices?

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# Loop refinement of an existing model
from modeller import *
from modeller.automodel import *

log.verbose()
env = environ()

# directories for input atom files
env.io.atom_files_directory = './:../atom_files'

# Create a new class based on 'loopmodel' so that we can redefine
# select_loop_atoms (necessary)
class MyLoop(loopmodel):
    # This routine picks the residues to be refined by loop modeling
    def select_loop_atoms(self):
        # One loop from residue 19 to 28 inclusive
    return selection(self.residue_range('273', '283'))
        #return selection(self.residue_range('1:', '4:'))

m = MyLoop(env,
           inimodel='input.pdb', # initial model of the target
           sequence='model')               # code of the target

m.loop.starting_model= 0   &nbs p;       # index of the first loop model
m.loop.ending_model  = 100           # index of the last loop model
m.loop.md_level = refine.very_fast  # loop refinement method

m.make()

KeyError: 'No such residue: 206:'