loop modeling and hydrogen atoms
Hi, I generated a model with all hydrogens using allhmodel. Now I want to refine a loop in this model using the script below. However, the hydrogens are being removed in the generated models.
Would you help me? from modeller import * from modeller.automodel import *
log.verbose() env = environ()
env.io.atom_files_directory = ['.', '../atom_files']
# Read in HETATM records from template PDBs env.io.hetatm = True env.io.water = True env.io.hydrogen = True
# Create a new class based on 'loopmodel' so that we can redefine # select_loop_atoms class MyLoop(loopmodel): # This routine picks the residues to be refined by loop modeling def select_loop_atoms(self): # Two residue ranges (both will be refined simultaneously) return selection(self.residue_range('399:', '406:'))
m = MyLoop(env, inimodel='Model172.pdb', sequence='protein', loop_assess_methods=(assess.DOPE, assess.GA341))
m.loop.starting_model= 1 # index of the first loop model m.loop.ending_model = 200 # index of the last loop model m.loop.md_level = refine.very_fast # loop refinement method
m.make()
# Get a list of all successfully built models from m.loop.outputs ok_models = filter(lambda x: x['failure'] is None, m.loop.outputs)
# Rank the models by DOPE score key = 'DOPE score' ok_models.sort(lambda a,b: cmp(a[key], b[key]))
# Get top model m = ok_models[0]
print "Top model 1: %s (DOPE score %.3f)" % (m['name'], m[key]) m = ok_models[1]
print "Top model 2: %s (DOPE score %.3f)" % (m['name'], m[key]) m = ok_models[2]
print "Top model 3: %s (DOPE score %.3f)" % (m['name'], m[key]) m = ok_models[3]
print "Top model 4: %s (DOPE score %.3f)" % (m['name'], m[key]) m = ok_models[4]
print "Top model 5: %s (DOPE score %.3f)" % (m['name'], m[key])
------------------------------------- Flavio Augusto Vicente Seixas Laboratory of Structural Biochemistry Department of Biochemistry Universidade Estadual de Maringá, PR, Brazil http://www.uem.br
On 7/25/16 5:43 AM, flavio seixas wrote: > I generated a model with all hydrogens using allhmodel. > Now I want to refine a loop in this model using the script below. > However, the hydrogens are being removed in the generated models.
Loop modeling relies on a statistical potential derived from pairwise atom-atom distances extracted from known PDB files. Most PDB files don't contain hydrogens, so this potential includes no terms for interactions with hydrogen. (Even if it did, including hydrogens roughly doubles the number of atoms in your system, which would result in a more rugged energy surface and also roughly quadruple the compute time for little benefit.) If you really want hydrogens in your models, add them in later.
Ben Webb, Modeller Caretaker
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flavio seixas
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Modeller Caretaker