Package schrodinger :: Package structutils :: Package interactions :: Module salt_bridge
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Module salt_bridge

Find salt-bridge interactions.

Examples

Find all salt bridge interactions within a protein:

   st = StructureReader("protein.maegz").next()
   for (atom1, atom2) in SaltBridgeFinder.find(st):
       print "Salt bridge between atoms %i and %i" % (atom1, atom2)

Find all salt bridges within a single protein chain:

   st = StructureReader("protein.maegz").next()
   atoms = st.chain["C"].getAtomIndices()
   for (atom1, atom2) in SaltBridgeFinder.find(st, atoms):
       print "Salt bridge between atoms %i and %i" % (atom1, atom2)

Find all salt bridges between a protein and a ligand:

   reader = StructureReader("protein_and_ligand.maegz")
   prot = reader.next()
   lig = reader.next()
   for (atom1, atom2) in SaltBridgeFinder.find(prot, struc2=lig):
       print "Salt bridge between atoms %i and %i" % (atom1, atom2)
Classes [hide private]
  OrderBy
  SaltBridgeFinder
Find salt-bridge interactions.
Functions [hide private]
list
get_salt_bridges(struc1, group1=None, struc2=None, group2=None, cutoff=5, order_by=<OrderBy.AnionCation: 1>)
Calculate all salt bridges within or between the specified atoms.
list
_get_wrapped_sb_list(struc1, group1, struc2, group2, cutoff)
Get the salt bridge list returned by schrodinger.infra.structure.get_salt_bridges.
schrodinger.infra.structure.Structure or NoneType
_convert_struc(struc)
Convert a structure from a schrodinger.structure.Structure object to a schrodinger.infra.structure.Structure object.
mmbitset.Bitset
_convert_group(group, struc)
Convert a list of atom indices to a bitset.
 
_convert_salt_bridge(salt_bridge)
Convert schrodinger.infra.structure.SaltBridge object to a tuple of (anion, cation) schrodinger.structure._StructureAtom objects.
 
_convert_atom(infra_atom)
Convert a schrodinger.infra.structure.StructureAtom object into a schrodinger.structure._StructureAtom
tuple
_to_input_order(salt_bridge, struc1, bs1)
Switch the salt bridge tuple from (anion, cation) order to input order.
Variables [hide private]
  DEFAULT_MAX_DIST = 4.0
  __package__ = 'schrodinger.structutils.interactions'
Function Details [hide private]

get_salt_bridges(struc1, group1=None, struc2=None, group2=None, cutoff=5, order_by=<OrderBy.AnionCation: 1>)

 

Calculate all salt bridges within or between the specified atoms. If struc2 or group2 are given, then this function will return salt bridges between the two structures/groups of atoms. If neither struc2 nor group2 are given, then this function will return salt bridges within a single structure/group of atoms.

Parameters:
  • struc1 (schrodinger.structure.Structure) - The structure to analyze
  • group1 (list) - The list of atom indices in struc1 to analyze. If not given, all atoms in struc1 will be analyzed.
  • struc2 (schrodinger.structure.Structure) - The second structure to analyze. If group2 is given but struc2 is not, then struc1 will be used.
  • group2 (list) - The list of atom indices in struc2 to analyze. If struc2 is given but group2 is not, then all atoms in struc2 will be analyzed.
  • cutoff (float) - The maximum distance allowed for salt bridges
  • order_by (OrderBy) - How the returned salt bridge atom should be ordered. If OrderBy.AnionCation, then each salt bridge will be returned as a tuple of (anion atom, cation atom). If OrderBy.InputOrder, then each salt bridge will be returned as a tuple of (atom from struc1/group1, atom from struc2/group2).
Returns: list
A list of salt bridges, where each salt bridge is represented by a tuple of two schrodinger.structure._StructureAtom objects.

_get_wrapped_sb_list(struc1, group1, struc2, group2, cutoff)

 

Get the salt bridge list returned by schrodinger.infra.structure.get_salt_bridges.

Parameters:
  • struc1 (schrodinger.structure.Structure) - The structure to analyze
  • group1 (list) - The list of atom indices in struc1 to analyze. If not given, all atoms in struc1 will be analyzed.
  • struc2 (schrodinger.structure.Structure) - The second structure to analyze. If group2 is given but struc2 is not, then struc1 will be used.
  • group2 (list) - The list of atom indices in struc2 to analyze. If struc2 is given but group2 is not, then all atoms in struc2 will be analyzed.
  • cutoff (float) - The maximum distance allowed for salt bridges
Returns: list
A list of salt bridges, where each salt bridge is represented by a tuple of two schrodinger.infra.structure.StructureAtom objects in (anion, cation) order.

_convert_struc(struc)

 

Convert a structure from a schrodinger.structure.Structure object to a schrodinger.infra.structure.Structure object.

Parameters:
Returns: schrodinger.infra.structure.Structure or NoneType
The converted structure.

_convert_group(group, struc)

 

Convert a list of atom indices to a bitset.

Parameters:
  • group (list) - A list of atom indices. If None, the bitset will contain all atoms in struc.
  • struc (schrodinger.structure.Structure) - The structure that the group atom indices refer to
Returns: mmbitset.Bitset
The bitset

_to_input_order(salt_bridge, struc1, bs1)

 

Switch the salt bridge tuple from (anion, cation) order to input order.

Parameters:
Returns: tuple
The re-ordered salt bridge, as a tuple of schrodinger.structure._StructureAtom objects.