/
pose_scoring.py
244 lines (193 loc) · 6.34 KB
/
pose_scoring.py
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"""
Utilities to score protein-ligand poses using DeepChem.
"""
import numpy as np
def pairwise_distances(coords1: np.ndarray, coords2: np.ndarray) -> np.ndarray:
"""Returns matrix of pairwise Euclidean distances.
Parameters
----------
coords1: np.ndarray
A numpy array of shape `(N, 3)`
coords2: np.ndarray
A numpy array of shape `(M, 3)`
Returns
-------
np.ndarray
A `(N,M)` array with pairwise distances.
"""
return np.sum((coords1[None, :] - coords2[:, None])**2, -1)**0.5
def cutoff_filter(d: np.ndarray, x: np.ndarray, cutoff=8.0) -> np.ndarray:
"""Applies a cutoff filter on pairwise distances
Parameters
----------
d: np.ndarray
Pairwise distances matrix. A numpy array of shape `(N, M)`
x: np.ndarray
Matrix of shape `(N, M)`
cutoff: float, optional (default 8)
Cutoff for selection in Angstroms
Returns
-------
np.ndarray
A `(N,M)` array with values where distance is too large thresholded to 0.
"""
return np.where(d < cutoff, x, np.zeros_like(x))
def vina_nonlinearity(c: np.ndarray, w: float, Nrot: int) -> np.ndarray:
"""Computes non-linearity used in Vina.
Parameters
----------
c: np.ndarray
A numpy array of shape `(N, M)`
w: float
Weighting term
Nrot: int
Number of rotatable bonds in this molecule
Returns
-------
np.ndarray
A `(N, M)` array with activations under a nonlinearity.
"""
out_tensor = c / (1 + w * Nrot)
return out_tensor
def vina_repulsion(d: np.ndarray) -> np.ndarray:
"""Computes Autodock Vina's repulsion interaction term.
Parameters
----------
d: np.ndarray
A numpy array of shape `(N, M)`.
Returns
-------
np.ndarray
A `(N, M)` array with repulsion terms.
"""
return np.where(d < 0, d**2, np.zeros_like(d))
def vina_hydrophobic(d: np.ndarray) -> np.ndarray:
"""Computes Autodock Vina's hydrophobic interaction term.
Here, d is the set of surface distances as defined in [1]_
Parameters
----------
d: np.ndarray
A numpy array of shape `(N, M)`.
Returns
-------
np.ndarray
A `(N, M)` array of hydrophoboic interactions in a piecewise linear curve.
References
----------
.. [1] Jain, Ajay N. "Scoring noncovalent protein-ligand interactions:
a continuous differentiable function tuned to compute binding affinities."
Journal of computer-aided molecular design 10.5 (1996): 427-440.
"""
out_tensor = np.where(d < 0.5, np.ones_like(d),
np.where(d < 1.5, 1.5 - d, np.zeros_like(d)))
return out_tensor
def vina_hbond(d: np.ndarray) -> np.ndarray:
"""Computes Autodock Vina's hydrogen bond interaction term.
Here, d is the set of surface distances as defined in [1]_
Parameters
----------
d: np.ndarray
A numpy array of shape `(N, M)`.
Returns
-------
np.ndarray
A `(N, M)` array of hydrophoboic interactions in a piecewise linear curve.
References
----------
.. [1] Jain, Ajay N. "Scoring noncovalent protein-ligand interactions:
a continuous differentiable function tuned to compute binding affinities."
Journal of computer-aided molecular design 10.5 (1996): 427-440.
"""
out_tensor = np.where(
d < -0.7, np.ones_like(d),
np.where(d < 0, (1.0 / 0.7) * (0 - d), np.zeros_like(d)))
return out_tensor
def vina_gaussian_first(d: np.ndarray) -> np.ndarray:
"""Computes Autodock Vina's first Gaussian interaction term.
Here, d is the set of surface distances as defined in [1]_
Parameters
----------
d: np.ndarray
A numpy array of shape `(N, M)`.
Returns
-------
np.ndarray
A `(N, M)` array of gaussian interaction terms.
References
----------
.. [1] Jain, Ajay N. "Scoring noncovalent protein-ligand interactions:
a continuous differentiable function tuned to compute binding affinities."
Journal of computer-aided molecular design 10.5 (1996): 427-440.
"""
out_tensor = np.exp(-(d / 0.5)**2)
return out_tensor
def vina_gaussian_second(d: np.ndarray) -> np.ndarray:
"""Computes Autodock Vina's second Gaussian interaction term.
Here, d is the set of surface distances as defined in [1]_
Parameters
----------
d: np.ndarray
A numpy array of shape `(N, M)`.
Returns
-------
np.ndarray
A `(N, M)` array of gaussian interaction terms.
References
----------
.. [1] Jain, Ajay N. "Scoring noncovalent protein-ligand interactions:
a continuous differentiable function tuned to compute binding affinities."
Journal of computer-aided molecular design 10.5 (1996): 427-440.
"""
out_tensor = np.exp(-((d - 3) / 2)**2)
return out_tensor
def weighted_linear_sum(w: np.ndarray, x: np.ndarray) -> np.ndarray:
"""Computes weighted linear sum.
Parameters
----------
w: np.ndarray
A numpy array of shape `(N,)`
x: np.ndarray
A numpy array of shape `(N, M, L)`
Returns
-------
np.ndarray
A numpy array of shape `(M, L)`
"""
return np.tensordot(w, x, axes=1)
def vina_energy_term(coords1: np.ndarray, coords2: np.ndarray,
weights: np.ndarray, wrot: float, Nrot: int) -> np.ndarray:
"""Computes the Vina Energy function for two molecular conformations
Parameters
----------
coords1: np.ndarray
Molecular coordinates of shape `(N, 3)`
coords2: np.ndarray
Molecular coordinates of shape `(M, 3)`
weights: np.ndarray
A numpy array of shape `(5,)`. The 5 values are weights for repulsion interaction term,
hydrophobic interaction term, hydrogen bond interaction term,
first Gaussian interaction term and second Gaussian interaction term.
wrot: float
The scaling factor for nonlinearity
Nrot: int
Number of rotatable bonds in this calculation
Returns
-------
np.ndarray
A scalar value with free energy
"""
# TODO(rbharath): The autodock vina source computes surface distances
# which take into account the van der Waals radius of each atom type.
dists = pairwise_distances(coords1, coords2)
repulsion = vina_repulsion(dists)
hydrophobic = vina_hydrophobic(dists)
hbond = vina_hbond(dists)
gauss_1 = vina_gaussian_first(dists)
gauss_2 = vina_gaussian_second(dists)
# Shape (N, M)
interactions = weighted_linear_sum(
weights, np.array([repulsion, hydrophobic, hbond, gauss_1, gauss_2]))
# Shape (N, M)
thresholded = cutoff_filter(dists, interactions)
free_energies = vina_nonlinearity(thresholded, wrot, Nrot)
return np.sum(free_energies)