# Copyright 2024 ByteDance and/or its affiliates. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import argparse import copy import functools import os import re from collections import defaultdict from typing import Mapping, Sequence import biotite.structure as struc import numpy as np import torch from biotite.structure import AtomArray from biotite.structure.io import pdbx from biotite.structure.io.pdb import PDBFile from protenix.data.constants import DNA_STD_RESIDUES, PRO_STD_RESIDUES, RNA_STD_RESIDUES def remove_numbers(s: str) -> str: """ Remove numbers from a string. Args: s (str): input string Returns: str: a string with numbers removed. """ return re.sub(r"\d+", "", s) def int_to_letters(n: int) -> str: """ Convert int to letters. Useful for converting chain index to label_asym_id. Args: n (int): int number Returns: str: letters. e.g. 1 -> A, 2 -> B, 27 -> AA, 28 -> AB """ result = "" while n > 0: n, remainder = divmod(n - 1, 26) result = chr(65 + remainder) + result return result def get_inter_residue_bonds(atom_array: AtomArray) -> np.ndarray: """get inter residue bonds by checking chain_id and res_id Args: atom_array (AtomArray): Biotite AtomArray, must have chain_id and res_id Returns: np.ndarray: inter residue bonds, shape = (n,2) """ if atom_array.bonds is None: return [] idx_i = atom_array.bonds._bonds[:, 0] idx_j = atom_array.bonds._bonds[:, 1] chain_id_diff = atom_array.chain_id[idx_i] != atom_array.chain_id[idx_j] res_id_diff = atom_array.res_id[idx_i] != atom_array.res_id[idx_j] diff_mask = chain_id_diff | res_id_diff inter_residue_bonds = atom_array.bonds._bonds[diff_mask] inter_residue_bonds = inter_residue_bonds[:, :2] # remove bond type return inter_residue_bonds def get_starts_by( atom_array: AtomArray, by_annot: str, add_exclusive_stop=False ) -> np.ndarray: """get start indices by given annotation in an AtomArray Args: atom_array (AtomArray): Biotite AtomArray by_annot (str): annotation to group by, eg: 'chain_id', 'res_id', 'res_name' add_exclusive_stop (bool, optional): add exclusive stop (len(atom_array)). Defaults to False. Returns: np.ndarray: start indices of each group, shape = (n,), eg: [0, 10, 20, 30, 40] """ annot = getattr(atom_array, by_annot) # If annotation change, a new start annot_change_mask = annot[1:] != annot[:-1] # Convert mask to indices # Add 1, to shift the indices from the end of a residue # to the start of a new residue starts = np.where(annot_change_mask)[0] + 1 # The first start is not included yet -> Insert '[0]' if add_exclusive_stop: return np.concatenate(([0], starts, [atom_array.array_length()])) else: return np.concatenate(([0], starts)) def atom_select(atom_array: AtomArray, select_dict: dict, as_mask=False) -> np.ndarray: """return index of atom_array that match select_dict Args: atom_array (AtomArray): Biotite AtomArray select_dict (dict): select dict, eg: {'element': 'C'} as_mask (bool, optional): return mask of atom_array. Defaults to False. Returns: np.ndarray: index of atom_array that match select_dict """ mask = np.ones(len(atom_array), dtype=bool) for k, v in select_dict.items(): mask = mask & (getattr(atom_array, k) == v) if as_mask: return mask else: return np.where(mask)[0] def get_ligand_polymer_bond_mask( atom_array: AtomArray, lig_include_ions=False ) -> np.ndarray: """ Ref AlphaFold3 SI Chapter 3.7.1. Get bonds between the bonded ligand and its parent chain. Args: atom_array (AtomArray): biotite atom array object. lig_include_ions (bool): whether to include ions in the ligand. Returns: np.ndarray: bond records between the bonded ligand and its parent chain. e.g. np.array([[atom1, atom2, bond_order]...]) """ if not lig_include_ions: # bonded ligand exclude ions unique_chain_id, counts = np.unique( atom_array.label_asym_id, return_counts=True ) chain_id_to_count_map = dict(zip(unique_chain_id, counts)) ions_mask = np.array( [ chain_id_to_count_map[label_asym_id] == 1 for label_asym_id in atom_array.label_asym_id ] ) lig_mask = (atom_array.mol_type == "ligand") & ~ions_mask else: lig_mask = atom_array.mol_type == "ligand" # identify polymer by mol_type (protein, rna, dna, ligand) polymer_mask = np.isin(atom_array.mol_type, ["protein", "rna", "dna"]) idx_i = atom_array.bonds._bonds[:, 0] idx_j = atom_array.bonds._bonds[:, 1] lig_polymer_bond_indices = np.where( (lig_mask[idx_i] & polymer_mask[idx_j]) | (lig_mask[idx_j] & polymer_mask[idx_i]) )[0] if lig_polymer_bond_indices.size == 0: # no ligand-polymer bonds lig_polymer_bonds = np.empty((0, 3)).astype(int) else: lig_polymer_bonds = atom_array.bonds._bonds[ lig_polymer_bond_indices ] # np.array([[atom1, atom2, bond_order]...]) return lig_polymer_bonds @functools.lru_cache def parse_pdb_cluster_file_to_dict( cluster_file: str, remove_uniprot: bool = True ) -> dict[str, tuple]: """parse PDB cluster file, and return a pandas dataframe example cluster file: https://cdn.rcsb.org/resources/sequence/clusters/clusters-by-entity-40.txt Args: cluster_file (str): cluster_file path Returns: dict(str, tuple(str, str)): {pdb_id}_{entity_id} --> [cluster_id, cluster_size] """ pdb_cluster_dict = {} with open(cluster_file) as f: for line in f: pdb_clusters = [] for ids in line.strip().split(): if remove_uniprot: if ids.startswith("AF_") or ids.startswith("MA_"): continue pdb_clusters.append(ids) cluster_size = len(pdb_clusters) if cluster_size == 0: continue # use first member as cluster id. cluster_id = f"pdb_cluster_{pdb_clusters[0]}" for ids in pdb_clusters: pdb_cluster_dict[ids.lower()] = (cluster_id, cluster_size) return pdb_cluster_dict def get_clean_data(atom_array: AtomArray) -> AtomArray: """ Removes unresolved atoms from the AtomArray. Args: atom_array (AtomArray): The input AtomArray containing atoms. Returns: AtomArray: A new AtomArray with unresolved atoms removed. """ atom_array_wo_unresol = atom_array.copy() atom_array_wo_unresol = atom_array[atom_array.is_resolved] return atom_array_wo_unresol def save_atoms_to_cif( output_cif_file: str, atom_array: AtomArray, entity_poly_type: dict[str, str], pdb_id: str, ) -> None: """ Save atom array data to a CIF file. Args: output_cif_file (str): The output path for saving the atom array in CIF format. atom_array (AtomArray): The atom array to be saved. entity_poly_type: The entity poly type information. pdb_id: The PDB ID for the entry. """ cifwriter = CIFWriter(atom_array, entity_poly_type) cifwriter.save_to_cif( output_path=output_cif_file, entry_id=pdb_id, include_bonds=False, ) def save_structure_cif( atom_array: AtomArray, pred_coordinate: torch.Tensor, output_fpath: str, entity_poly_type: dict[str, str], pdb_id: str, ): """ Save the predicted structure to a CIF file. Args: atom_array (AtomArray): The original AtomArray containing the structure. pred_coordinate (torch.Tensor): The predicted coordinates for the structure. output_fpath (str): The output file path for saving the CIF file. entity_poly_type (dict[str, str]): The entity poly type information. pdb_id (str): The PDB ID for the entry. """ pred_atom_array = copy.deepcopy(atom_array) pred_pose = pred_coordinate.cpu().numpy() pred_atom_array.coord = pred_pose save_atoms_to_cif( output_fpath, pred_atom_array, entity_poly_type, pdb_id, ) # save pred coordinates wo unresolved atoms if hasattr(atom_array, "is_resolved"): pred_atom_array_wo_unresol = get_clean_data(pred_atom_array) save_atoms_to_cif( output_fpath.replace(".cif", "_wounresol.cif"), pred_atom_array_wo_unresol, entity_poly_type, pdb_id, ) class CIFWriter: """ Write AtomArray to cif. """ def __init__(self, atom_array: AtomArray, entity_poly_type: dict[str, str] = None): """ Args: atom_array (AtomArray): Biotite AtomArray object. entity_poly_type (dict[str, str], optional): A dict of label_entity_id to entity_poly_type. Defaults to None. If None, "the entity_poly" and "entity_poly_seq" will not be written to the cif. """ self.atom_array = atom_array self.entity_poly_type = entity_poly_type def _get_entity_poly_and_entity_poly_seq_block(self): entity_poly = defaultdict(list) for entity_id, entity_type in self.entity_poly_type.items(): label_asym_ids = np.unique( self.atom_array.label_asym_id[ self.atom_array.label_entity_id == entity_id ] ) label_asym_ids_str = ",".join(label_asym_ids) if label_asym_ids_str == "": # The entity not in current atom_array continue entity_poly["entity_id"].append(entity_id) entity_poly["pdbx_strand_id"].append(label_asym_ids_str) entity_poly["type"].append(entity_type) entity_poly_seq = defaultdict(list) for entity_id, label_asym_ids_str in zip( entity_poly["entity_id"], entity_poly["pdbx_strand_id"] ): first_label_asym_id = label_asym_ids_str.split(",")[0] first_asym_chain = self.atom_array[ self.atom_array.label_asym_id == first_label_asym_id ] chain_starts = struc.get_chain_starts( first_asym_chain, add_exclusive_stop=True ) asym_chain = first_asym_chain[ chain_starts[0] : chain_starts[1] ] # ensure the asym chain is a single chain res_starts = struc.get_residue_starts(asym_chain, add_exclusive_stop=False) asym_chain_entity_id = asym_chain[res_starts].label_entity_id.tolist() asym_chain_hetero = [ "n" if not i else "y" for i in asym_chain[res_starts].hetero ] asym_chain_res_name = asym_chain[res_starts].res_name.tolist() asym_chain_res_id = asym_chain[res_starts].res_id.tolist() entity_poly_seq["entity_id"].extend(asym_chain_entity_id) entity_poly_seq["hetero"].extend(asym_chain_hetero) entity_poly_seq["mon_id"].extend(asym_chain_res_name) entity_poly_seq["num"].extend(asym_chain_res_id) block_dict = { "entity_poly": pdbx.CIFCategory(entity_poly), "entity_poly_seq": pdbx.CIFCategory(entity_poly_seq), } return block_dict def save_to_cif( self, output_path: str, entry_id: str = None, include_bonds: bool = False ): """ Save AtomArray to cif. Args: output_path (str): Output path of cif file. entry_id (str, optional): The value of "_entry.id" in cif. Defaults to None. If None, the entry_id will be the basename of output_path (without ".cif" extension). include_bonds (bool, optional): Whether to include bonds in the cif. Defaults to False. If set to True and `array` has associated ``bonds`` , the intra-residue bonds will be written into the ``chem_comp_bond`` category. Inter-residue bonds will be written into the ``struct_conn`` independent of this parameter. """ if entry_id is None: entry_id = os.path.basename(output_path).replace(".cif", "") block_dict = {"entry": pdbx.CIFCategory({"id": entry_id})} if self.entity_poly_type: block_dict.update(self._get_entity_poly_and_entity_poly_seq_block()) block = pdbx.CIFBlock(block_dict) cif = pdbx.CIFFile( { os.path.basename(output_path).replace(".cif", "") + "_predicted_by_protenix": block } ) pdbx.set_structure(cif, self.atom_array, include_bonds=include_bonds) block = cif.block atom_site = block.get("atom_site") occ = atom_site.get("occupancy") if occ is None: atom_site["occupancy"] = np.ones(len(self.atom_array), dtype=float) atom_site["label_entity_id"] = self.atom_array.label_entity_id cif.write(output_path) def make_dummy_feature( features_dict: Mapping[str, torch.Tensor], dummy_feats: Sequence = ["msa"], ) -> dict[str, torch.Tensor]: num_token = features_dict["token_index"].shape[0] num_atom = features_dict["atom_to_token_idx"].shape[0] num_msa = 1 num_templ = 4 num_pockets = 30 feat_shape, _ = get_data_shape_dict( num_token=num_token, num_atom=num_atom, num_msa=num_msa, num_templ=num_templ, num_pocket=num_pockets, ) for feat_name in dummy_feats: if feat_name not in ["msa", "template"]: cur_feat_shape = feat_shape[feat_name] features_dict[feat_name] = torch.zeros(cur_feat_shape) if "msa" in dummy_feats: # features_dict["msa"] = features_dict["restype"].unsqueeze(0) features_dict["msa"] = torch.nonzero(features_dict["restype"])[:, 1].unsqueeze( 0 ) assert features_dict["msa"].shape == feat_shape["msa"] features_dict["has_deletion"] = torch.zeros(feat_shape["has_deletion"]) features_dict["deletion_value"] = torch.zeros(feat_shape["deletion_value"]) features_dict["profile"] = features_dict["restype"] assert features_dict["profile"].shape == feat_shape["profile"] features_dict["deletion_mean"] = torch.zeros(feat_shape["deletion_mean"]) for key in [ "prot_pair_num_alignments", "prot_unpair_num_alignments", "rna_pair_num_alignments", "rna_unpair_num_alignments", ]: features_dict[key] = torch.tensor(0, dtype=torch.int32) if "template" in dummy_feats: features_dict["template_restype"] = ( torch.ones(feat_shape["template_restype"]) * 31 ) # gap features_dict["template_all_atom_mask"] = torch.zeros( feat_shape["template_all_atom_mask"] ) features_dict["template_all_atom_positions"] = torch.zeros( feat_shape["template_all_atom_positions"] ) return features_dict def data_type_transform( feat_or_label_dict: Mapping[str, torch.Tensor] ) -> tuple[dict[str, torch.Tensor], dict[str, torch.Tensor], AtomArray]: for key, value in feat_or_label_dict.items(): if key in IntDataList: feat_or_label_dict[key] = value.to(torch.long) return feat_or_label_dict # List of "index" or "type" data # Their data type should be int IntDataList = [ "residue_index", "token_index", "asym_id", "entity_id", "sym_id", "ref_space_uid", "template_restype", "atom_to_token_idx", "atom_to_tokatom_idx", "frame_atom_index", "msa", "entity_mol_id", "mol_id", "mol_atom_index", ] # shape of the data def get_data_shape_dict(num_token, num_atom, num_msa, num_templ, num_pocket): """ Generate a dictionary containing the shapes of all data. Args: num_token (int): Number of tokens. num_atom (int): Number of atoms. num_msa (int): Number of MSA sequences. num_templ (int): Number of templates. num_pocket (int): Number of pockets to the same interested ligand. Returns: dict: A dictionary containing the shapes of all data. """ # Features in AlphaFold3 SI Table5 feat = { # Token features "residue_index": (num_token,), "token_index": (num_token,), "asym_id": (num_token,), "entity_id": (num_token,), "sym_id": (num_token,), "restype": (num_token, 32), # chain permutation features "entity_mol_id": (num_atom,), "mol_id": (num_atom,), "mol_atom_index": (num_atom,), # Reference features "ref_pos": (num_atom, 3), "ref_mask": (num_atom,), "ref_element": (num_atom, 128), # note: 128 elem in the paper "ref_charge": (num_atom,), "ref_atom_name_chars": (num_atom, 4, 64), "ref_space_uid": (num_atom,), # Msa features # "msa": (num_msa, num_token, 32), "msa": (num_msa, num_token), "has_deletion": (num_msa, num_token), "deletion_value": (num_msa, num_token), "profile": (num_token, 32), "deletion_mean": (num_token,), # Template features "template_restype": (num_templ, num_token), "template_all_atom_mask": (num_templ, num_token, 37), "template_all_atom_positions": (num_templ, num_token, 37, 3), "template_pseudo_beta_mask": (num_templ, num_token), "template_backbone_frame_mask": (num_templ, num_token), "template_distogram": (num_templ, num_token, num_token, 39), "template_unit_vector": (num_templ, num_token, num_token, 3), # Bond features "token_bonds": (num_token, num_token), } # Extra features needed extra_feat = { # Input features "atom_to_token_idx": (num_atom,), # after crop "atom_to_tokatom_idx": (num_atom,), # after crop "pae_rep_atom_mask": (num_atom,), # same as "pae_rep_atom_mask" in label_dict "is_distillation": (1,), } # Label label = { "coordinate": (num_atom, 3), "coordinate_mask": (num_atom,), # "centre_atom_mask": (num_atom,), # "centre_centre_distance": (num_token, num_token), # "centre_centre_distance_mask": (num_token, num_token), "distogram_rep_atom_mask": (num_atom,), "pae_rep_atom_mask": (num_atom,), "plddt_m_rep_atom_mask": (num_atom,), "modified_res_mask": (num_atom,), "bond_mask": (num_atom, num_atom), "is_protein": (num_atom,), # Atom level, not token level "is_rna": (num_atom,), "is_dna": (num_atom,), "is_ligand": (num_atom,), "has_frame": (num_token,), # move to input_feature_dict? "frame_atom_index": (num_token, 3), # atom index after crop "resolution": (1,), # Metrics "interested_ligand_mask": ( num_pocket, num_atom, ), "pocket_mask": ( num_pocket, num_atom, ), } # Merged all_feat = {**feat, **extra_feat} return all_feat, label def get_lig_lig_bonds( atom_array: AtomArray, lig_include_ions: bool = False ) -> np.ndarray: """ Get all inter-ligand bonds in order to create "token_bonds". Args: atom_array (AtomArray): biotite AtomArray object with "mol_type" attribute. lig_include_ions (bool, optional): . Defaults to False. Returns: np.ndarray: inter-ligand bonds, e.g. np.array([[atom1, atom2, bond_order]...]) """ if not lig_include_ions: # bonded ligand exclude ions unique_chain_id, counts = np.unique( atom_array.label_asym_id, return_counts=True ) chain_id_to_count_map = dict(zip(unique_chain_id, counts)) ions_mask = np.array( [ chain_id_to_count_map[label_asym_id] == 1 for label_asym_id in atom_array.label_asym_id ] ) lig_mask = (atom_array.mol_type == "ligand") & ~ions_mask else: lig_mask = atom_array.mol_type == "ligand" chain_res_id = np.vstack((atom_array.label_asym_id, atom_array.res_id)).T idx_i = atom_array.bonds._bonds[:, 0] idx_j = atom_array.bonds._bonds[:, 1] ligand_ligand_bond_indices = np.where( (lig_mask[idx_i] & lig_mask[idx_j]) & np.any(chain_res_id[idx_i] != chain_res_id[idx_j], axis=1) )[0] if ligand_ligand_bond_indices.size == 0: # no ligand-polymer bonds lig_polymer_bonds = np.empty((0, 3)).astype(int) else: lig_polymer_bonds = atom_array.bonds._bonds[ligand_ligand_bond_indices] return lig_polymer_bonds def pdb_to_cif(input_fname: str, output_fname: str, entry_id: str = None): """ Convert PDB to CIF. Args: input_fname (str): input PDB file name output_fname (str): output CIF file name entry_id (str, optional): entry id. Defaults to None. """ pdbfile = PDBFile.read(input_fname) atom_array = pdbfile.get_structure(model=1, include_bonds=True, altloc="first") seq_to_entity_id = {} cnt = 0 chain_starts = struc.get_chain_starts(atom_array, add_exclusive_stop=True) # split chains by hetero new_chain_starts = [] for c_start, c_stop in zip(chain_starts[:-1], chain_starts[1:]): new_chain_starts.append(c_start) chain_start_hetero = atom_array.hetero[c_start] hetero_diff = np.where(atom_array.hetero[c_start:c_stop] != chain_start_hetero) if hetero_diff[0].shape[0] > 0: new_chain_start = c_start + hetero_diff[0][0] new_chain_starts.append(new_chain_start) new_chain_starts += [chain_starts[-1]] # # split HETATM chains by res id new_chain_starts2 = [] for c_start, c_stop in zip(new_chain_starts[:-1], new_chain_starts[1:]): new_chain_starts2.append(c_start) res_id_diff = np.diff(atom_array.res_id[c_start:c_stop]) uncont_res_starts = np.where(res_id_diff >= 1) if uncont_res_starts[0].shape[0] > 0: for res_start_atom_idx in uncont_res_starts[0]: new_chain_start = c_start + res_start_atom_idx + 1 # atom_array.hetero is True if "HETATM" if ( atom_array.hetero[new_chain_start] and atom_array.hetero[new_chain_start - 1] ): new_chain_starts2.append(new_chain_start) chain_starts = new_chain_starts2 + [chain_starts[-1]] label_entity_id = np.zeros(len(atom_array), dtype=np.int32) atom_index = np.arange(len(atom_array), dtype=np.int32) res_id = copy.deepcopy(atom_array.res_id) chain_id = copy.deepcopy(atom_array.chain_id) chain_count = 0 for c_start, c_stop in zip(chain_starts[:-1], chain_starts[1:]): chain_count += 1 new_chain_id = int_to_letters(chain_count) chain_id[c_start:c_stop] = new_chain_id chain_array = atom_array[c_start:c_stop] residue_starts = struc.get_residue_starts(chain_array, add_exclusive_stop=True) resname_seq = [name for name in chain_array[residue_starts[:-1]].res_name] resname_str = "_".join(resname_seq) if ( all([name in DNA_STD_RESIDUES for name in resname_seq]) and resname_str in seq_to_entity_id ): resname_seq = resname_seq[::-1] resname_str = "_".join(resname_seq) atom_index[c_start:c_stop] = atom_index[c_start:c_stop][::-1] if resname_str not in seq_to_entity_id: cnt += 1 seq_to_entity_id[resname_str] = cnt label_entity_id[c_start:c_stop] = seq_to_entity_id[resname_str] res_cnt = 1 for res_start, res_stop in zip(residue_starts[:-1], residue_starts[1:]): res_id[c_start:c_stop][res_start:res_stop] = res_cnt res_cnt += 1 atom_array = atom_array[atom_index] # add label entity id atom_array.set_annotation("label_entity_id", label_entity_id) entity_poly_type = {} for seq, entity_id in seq_to_entity_id.items(): resname_seq = seq.split("_") count = defaultdict(int) for name in resname_seq: if name in PRO_STD_RESIDUES: count["prot"] += 1 elif name in DNA_STD_RESIDUES: count["dna"] += 1 elif name in RNA_STD_RESIDUES: count["rna"] += 1 else: count["other"] += 1 if count["prot"] >= 2 and count["dna"] == 0 and count["rna"] == 0: entity_poly_type[entity_id] = "polypeptide(L)" elif count["dna"] >= 2 and count["rna"] == 0 and count["prot"] == 0: entity_poly_type[entity_id] = "polydeoxyribonucleotide" elif count["rna"] >= 2 and count["dna"] == 0 and count["prot"] == 0: entity_poly_type[entity_id] = "polyribonucleotide" else: # other entity type: ignoring continue # add label atom id atom_array.set_annotation("label_atom_id", atom_array.atom_name) # add label asym id atom_array.chain_id = chain_id # reset chain_id atom_array.set_annotation("label_asym_id", atom_array.chain_id) # add label seq id atom_array.res_id = res_id # reset res_id atom_array.set_annotation("label_seq_id", atom_array.res_id) w = CIFWriter(atom_array=atom_array, entity_poly_type=entity_poly_type) w.save_to_cif( output_fname, entry_id=entry_id or os.path.basename(output_fname), include_bonds=True, ) if __name__ == "__main__": parser = argparse.ArgumentParser() parser.add_argument( "--pdb_file", type=str, required=True, help="The pdb file to parse" ) parser.add_argument( "--cif_file", type=str, required=True, help="The cif file path to generate" ) args = parser.parse_args() pdb_to_cif(args.pdb_file, args.cif_file)