schrodinger.application.pathfinder.multiroute module

Functions to support multi-route enumeration (AKA “simple reaction enumeration” or “automated reaction enumeration”).

class schrodinger.application.pathfinder.multiroute.MultiRouteEnumerator(target_mol, reactions_dict, *, dedup=True, depth=None, descriptors='MolLogP, MolWt, NumChiralCenters, NumHAcceptors, NumHDonors, TPSA', frozen_atoms=frozenset(), libpath=None, max_per_route=1000, max_routes=100, no_core_hopping=False, product_property_filter_file=None, product_smarts_filter_file=None, ref_mols=None, ch_dist_tol=1.0, ch_ang_tol=15.0, bond_reactions=None, prefilter_reagents=None, fp_dir=None, fp_url=None, fp_namespace=None, **unused_args)

Bases: object

A generator of products following the multiroute enumeration protocol.

__init__(target_mol, reactions_dict, *, dedup=True, depth=None, descriptors='MolLogP, MolWt, NumChiralCenters, NumHAcceptors, NumHDonors, TPSA', frozen_atoms=frozenset(), libpath=None, max_per_route=1000, max_routes=100, no_core_hopping=False, product_property_filter_file=None, product_smarts_filter_file=None, ref_mols=None, ch_dist_tol=1.0, ch_ang_tol=15.0, bond_reactions=None, prefilter_reagents=None, fp_dir=None, fp_url=None, fp_namespace=None, **unused_args)
Parameters:
  • dedup (bool) – skip duplicate products (using SMILES for comparison)
  • depth (int or NoneType) – analysis depth (if None, increasing depths will be attempted until enough routes are found)
  • descriptors (list of str) – names of RDKit descriptors to compute for each product
  • frozen_atoms (set of int) – indexes (1-based) of atoms to keep in the product
  • libpath (list of str) – directories to search for reactant files
  • max_per_route (int) – maximum number of products per route
  • max_routes (int) – maximum number of routes to sample
  • no_core_hopping (bool) – don’t use the special core hopping mode even when possible
  • product_property_filter_file (str) – name of JSON file with product property filters
  • product_smarts_filter_file (str) – name of .cflt file with SMARTS patterns
  • ref_mols (list(Mol) or str) – reference molecules for similarity calculations
  • ch_dist_tol (float) – core-hopping distance tolerance in Angstroms (maximum allowed change in the distance between side chains, relative to the input structure)
  • ch_ang_tol (float) – core-hopping angle tolerance in degrees (maximum change bond vector angle for side chains, relative to the input structure)
  • bond_reactions – dict specifying which reactions are allowed to break certain bonds. Keys are tuples of two ints (sorted atom indexes); values are sets of reaction names.
  • bond_reactions – {(int, int): set(str)}
  • prefilter_reagents (int or NoneType) – number of most similar molecules to return.
Fp_dir:

directory to search for fingerprint files in addition to CWD
generate_mols()
Return type:generator of Mol
schrodinger.application.pathfinder.multiroute.get_fp_file(reactant_file, cache_dir, url_base=None, subdir='')

Get a fingerprint file for a given reactant file. First look at the cache dir; if not found, and a URL is supplied, try to download it from the server and write it to the cache dir.

For a reactant file named foo.pfx, the fingerprint file must be named foo-<sha1>.fp, where <sha1> is the SHA1 hash of foo.pfx.

Parameters:
  • reactant_file (str) – reactant file for which we are looking for fingerprints
  • cache_dir (str) – local directory where fingerprint files are/will be stored
Url_base:

base URL to try to download fingerprint files from
Subdir:

optionally, subdirectory of cache_dir and URL to use
Returns:

path to fingerprint file, if found; else None
Return type:

str or NoneType
schrodinger.application.pathfinder.multiroute.download_and_decompress(url, dest)

GET a gzip-compressed file from a URL and write it out, decompressed to the local filesystem. The contents are first downloaded to a temporary file and then renamed atomically. A locking mechanism is employed to try to prevent concurrent downloads of the same file.

Parameters:
  • url (str) – URL to download
  • dest (str) – destination filename
Returns:

dest if successful, else None (e.g. in case of 404)
Return type:

str or NoneType
schrodinger.application.pathfinder.multiroute.get_fp_basename(reactant_file)

Return the basename of the fingerprint file corresponding to the given reactant file, following the convention that for a reactant file named foo.pfx, the fingerprint file must be named foo-<sha1>.fp, where <sha1> is the SHA1 hash of foo.pfx.

Parameters:reactant_file (str) – reactant file
Returns:basename of fingerprint file
Return type:str
schrodinger.application.pathfinder.multiroute.get_sha1(filename)

Return the SHA1 hash of a file.

Parameters:filename (str) – input file
Returns:hex SHA1 digest of file contents
Return type:str
schrodinger.application.pathfinder.multiroute.get_lock(basename, max_wait, interval=1.0)

Create a <basename>.lock file on entry and remove it on exit. If the file already exists, wait up to max_wait seconds for the lock to clear. If the timeout is exceeded, assume that the lock is stale and ignore it.

This is a very rudimentary mechanism, but is good enough for the purposes of this module, which is just to _try_ to prevent simultaneous downloads of the same file, but where occasional collisions don’t hurt beyond the slight waste of bandwith and temporary use of disk space.

Parameters:
  • basename (str) – basename of lock file
  • max_wait (float) – maximum wait in seconds
  • interval (float) – time to sleep between attempts, in seconds
Returns:

context manager that removes lock file on exit
Return type:

contextlib._GeneratorContextManager
schrodinger.application.pathfinder.multiroute.has_variable_reactants(route)

Check if the route has at least one variable reactant.

Parameters:route (schrodinger.application.pathfinder.route.RouteNode) – route to analyze
Returns:does the route have at least one variable reactant?
Return type:bool
schrodinger.application.pathfinder.multiroute.is_core_sm(sm, core_atoms)

Check if a starting material node corresponds to a core.

Parameters:
Return type:

bool
schrodinger.application.pathfinder.multiroute.meta_sample(samples, dedup=True)

A generator that, on each cycle, picks a random element of samples and yields the next element from said sample. It never stops unless all samples raise StopIteration.

Each product gets annotated with properties representing the route that was used to make the molecule.

Parameters:
  • samples (list of iterator of Mol) – molecule samples
  • dedup (bool) – skip duplicate products
Returns:

molecule generator
Return type:

generator of rdkit.Chem.Mol
schrodinger.application.pathfinder.multiroute.measure_vectors(st, r1, c1, r2, c2)

Measure the distance and angle between two bond vectors. The distance is measured between atoms r1 and r2; the angle is between the c1-r1 and c2-r2 vectors.

Parameters:
  • st (schrodinger.structure.Structure) – structure to measure
  • r1 (int) – R-group attachment atom 1
  • c1 (int) – core atom 1
  • r2 (int) – R-group attachment atom 2
  • c2 (int) – core atom 2
Returns:

distance and angle
Return type:

float, float
schrodinger.application.pathfinder.multiroute.st_from_mol(mol)

Convert a Mol into a Structure, with 3D coordinates but no added hydrogens. Missing stereochemistry is tolerated.

Parameters:mol (rdkit.Chem.rdchem.Mol) – molecule
Returns:Structure
Return type:schrodinger.structure.Structure
schrodinger.application.pathfinder.multiroute.is_core(graph, free_component, frozen_components)

Check if the free_component subgraph should be considered a core, meaning that it is connected to more than one of the free_components.

Parameters:
  • graph (networkx.classes.graph.Graph) – molecular graph
  • free_component (set of int) – possible core atom indices
  • frozen_components (list of set of int) – possible sidechain atom indexes
Returns:

is it a core?
Return type:

bool
schrodinger.application.pathfinder.multiroute.apply_similarity_filters(products, args)

Implement the -sim_keep_percent and -sim_discard_percent functionality.

Parameters:
  • products (iterator of rdkit.Chem.Mol) – molecules to filter
  • args (argparse.Namespace) – command-line arguments
Returns:

filtered products and number of products to keep
Return type:

generator of rdkit.Chem.Mol, int
schrodinger.application.pathfinder.multiroute.analyze_frozen_atoms(mol, frozen_atoms)

Examine the molecular graph of the target molecule to partition it, based on the set of frozen atoms, into free regions and frozen regions. Also determine which free region is the core, if any.

A core in this context is a contiguous set of non-frozen atoms which is adjacent to two or more sets of frozen atoms (the side chains).

Jobs with two or more cores will abort immediately.

When there is a core, also measure the distances and angles between all the pairs of vectors leading from the core to the side chains. The resulting dict has pairs of atoms as keys, and (distance, angle) tuples as values.

In addition to the set of core atoms, a set of “core neighbors” is also returned. These are the non-core atoms that are directly connected to the core.

Parameters:
  • mol (rdkit.Chem.rdchem.Mol) – target molecule
  • frozen_atoms (set of int) – frozen atom indices
Returns:

measurements, core atoms, core neighbors
Return type:

dict {(int, int): (float, float)}, set of int, set of int
schrodinger.application.pathfinder.multiroute.generate_mols(*a, **d)

A generator of products following the multiroute enumeration protocol.

This is a thin functional wrapper around the MultiRouteEnumerator class. For arguments, see MultiRouteEnumerator.__init__.

Return type:generator of Mol
schrodinger.application.pathfinder.multiroute.write_products(products, filename, max_products)

Write out up to max_products from a mol iterator to a file.

Parameters:
  • products (iterator of Mol) – molecules to write
  • filename (str) – filename
  • max_products (int) – maximum number of structures to write