EvoPro is a genetic algorithm-based protein binder optimization pipeline, used in published work for in silico evolution of highly accurate, tight protein binders.
Now including multistate design, including our current unpublished work for conformational switch design!
PLEASE MAKE SURE TO USE "MAIN" BRANCH for code used in paper. Current working version is on "dev branch". Beta dockerized version is on "dockerized" branch.
Steps to set up a copy of EvoPro locally are detailed below.
Installation of Anaconda is required to load dependencies.
- Installing conda: conda-install-link
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Clone the repo:
git clone https://github.com/Kuhlman-Lab/evopro.git
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Clone our AF2 and ProteinMPNN repos:
git clone https://github.com/Kuhlman-Lab/alphafold.git git clone https://github.com/Kuhlman-Lab/proteinmpnn.git
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Load AlphaFold2 model weights from source using script: https://github.com/Kuhlman-Lab/alphafold/blob/main/setup/download_alphafold_params.sh
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Set up conda environment:
conda env create -n evopro -f setup_conda.yaml pip3 install --upgrade jax==0.3.25 jaxlib==0.3.25+cuda11.cudnn805 -f https://storage.googleapis.com/jax-releases/jax_cuda_releases.html python3 -m pip install /path/to/alphafold/alphafold/
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Set local paths at the top of each script in the evopro/run/ directory. (temporary step, will be removed when Docker support added)
Usage of EvoPro requires GPUs. The running directory should contain a sequence file with input sequences, and flags files for EvoPro specifications and AF2 specifications. See below for flag options and evopro/examples/ for examples of directory setups. pd1_binder and pd1_binder_nochainB are old examples using deprecated script - see examples/binder for updated version.
The residue_specs.json file should be generated from the sequence file. Specify sequence file and which residues to mutate in json.flags. (Include symmetry here if needed) Then, in the running directory:
python /path/to/evopro/run/generate_json.py @json.flagsYou can set options for EvoPro in the evopro.flags file. To run EvoPro, confirm availability of GPUs. Then,
conda activate evopro
python /path/to/evopro/run/run_evopro_binder.py @evopro.flagsSpecify your flag options in json.flags, and provide either a PDB or sequence file to extract starting sequences from. All flag options are listed below:
--pdb
default=None, type=str,
Path to and name of PDB file to extract chains and sequences. Alternatively use sequence file (below).
--sequence_file
default=None, type=str,
Path to and name of text file to extract chains and sequences. Only provide if there is no PDB file.
--mut_res
default=''”, type=str,
PDB chain and residue numbers to mutate, separated by commas. (Make sure there are no extraneous spaces between commas)
Here, you can use "*" to specify the whole chain (eg. A*), or "<" to specify all residues in a chain after a specific residue (eg B17<).
--default_mutres_setting
default='all', type=str,
Default setting for residues to mutate. Individual residues can be changed manually after generation of the file. Default is all. Other examples are “all-PC” (allow any mutation except proline and cysteine), “AVILMFYW” (specify which amino acids are allowed).
--output
default='', type=str,
path and name of output json file
--symmetric_res
default='', type=str,
PDB chain and residue numbers to force symmetry separated by a colon
Specify your AF2 options in af2.flags.
Notably, we suggest turning off MSA generation or providing pre-computed MSA and templates so that the AF2 runner will not have to query MMseqs server for every prediction (this will make runtime much longer and may cause errors).
To turn off MSA generation:
--msa_mode single_sequence
To use precomputed MSA:
--msa_mode single_sequence
--custom_msa_path /path/to/directory/with/a3m/files/
To use custom templates:
--use_templates
--custom_template_path templates
Since we have modified the original AF2 code to allow for custom template databases, you will have to make sure each .pdb file within the templates folder has a name consisting of 4 letters and numbers, essentially mimicking a file from the PDB database with a PDB code (although the file name does not actually have to be a real PDB code). Some examples could be “temp.pdb”, “1uzg.pdb”, “PPPP.pdb”, etc.
--input_dir
Default = current directory, type=str,
Path to directory that contains input files.
--num_iter
default=50, type=int,
Number of iterations of genetic algorithm. Default is 50.
--pool_size
Default=20, type=int,
Size of "genetic pool", or the number of sequences evaluated per iteration. Default is 20.
--pool_size_variable
Specify a file pool_sizes.txt with pool sizes for every iteration (or until pool size stops changing).
Defaults to False and uses constant pool size.
--num_gpus
default=1, type=int,
Number of gpus available. Default is 1.
--score_file
type=str,
Path and file name of python script containing the score function used to evaluate fitness of the alphafold predictions. Required.
--score_func
type=str,
Name of the score function in the score file used to evaluate fitness of the alphafold predictions. Required.
--score_func_2
default=None, type=str,
Name of the second score function in the score file used to evaluate fitness of the alphafold predictions after score_func_2 number of iterations (below) has been reached. Optional.
--score_func_2_iteration
default=30, type=int,
Number of iterations after which scoring function is switched to score_func_2. Default is 30 if score_func_2 is provided.
--define_contact_area
default=None, type=str,
User can specify residues on target interface to be targeted for contacts, passed to score function for parsing. Default is None.
--bonus_contacts
default=None, type=str,
User can define residues on target interface to be given a bonus for making contacts, followed by the distance cutoff. Default is None and 4A.
--penalize_contacts
default=None, type=str,
User can define residues on target interface to be given a penalty for making contacts, followed by the distance cutoff. Default is None and 8A.
--no_repeat_af2
Use this flag to specify if you DO NOT want AF2 to be run multiple times on the same sequence, and the score averaged. By default (without this flag) all sequences will be rescored every iteration until each sequence has been scored 5 times. Default is False.
--dont_write_compressed_data
Default is False.
--write_pdbs
Default is False.
--mpnn_freq
default=10, type=int,
Protein MPNN is used to refill the pool once every _ iterations. Default is 10.
--mpnn_iters
default=None, type=str,
Iteration numbers at which MPNN is used to refill the pool. Defaults to mpnn_freq if not provided.
--skip_mpnn
default=None, type=str,
Skip MPNN refilling in these iterations.
--mpnn_temp
default='0.1', type=str,
Protein MPNN is used to refill the pool at this sampling temperature. Default is 0.1.
--mpnn_temp_variable
Specify a file mpnn_temps.txt with temperatures for every call to MPNN (or until temp stops changing). Defaults to False and uses constant MPNN temp.
--mpnn_version
default="s_48_020", type=str,
Model version used to run MPNN. Default is s_48_020 (soluble).
--mpnn_bias_AA
default=None, type=str,
DOES NOT WORK YET. Path to json file containing bias dictionary for MPNN. Default is None.
--mpnn_bias_by_res
default=None, type=str,
Path to json file containing per residue bias dictionary for MPNN. Default is None.
--mpnn_chains
default=None, type=str,
Chains concatenated into a single pdb for MPNN. Default is None and it will use the first af2 prediction. Example: AB,B
--plot_confidences
Makes PAE and pLDDT plots for each output PDB. Default is False.
--plot_scores_avg
Plots average score value of pool over iterations. Default is False.
--plot_scores_median
Plots median score value of pool over iterations. Default is False.
--plot_scores_top
Plots highest score value of pool over iterations. Default is False.
--crossover_percent
default=0.2, type=float,
Fraction of pool refilled by crossover. Default is 0.2 (20% crossover).
--vary_length
default=0, type=int,
How much the length of mutable regions is allowed to vary. Default is 0.
--substitution_insertion_deletion_weights
default=None, type=str,
Specify probability of substitutions, insertions, and deletions (in that order) during mutation. Default is 0.8,0.1,0.1.
--mutation_percents
default=0.125, type=str,
Number of mutations made as a percentage of sequence length during random mutation only.
Default is 0.125 (12.5% of mutable sequence length) for every iteration. If more than one value is provided, number of iterations will be split evenly and assigned.
--af2_preds
default="AB", type=str,
Chain ID permutations to run through individual AF2 runs, separated by commas. Only used for multistate design. Default is just the complex AB.
--af2_preds_extra
default="AB", type=str,
DEPRECATED. Chain ID permutations to run through individual AF2 runs, separated by commas, in addition to the complex.
--rmsd_func
default=None, type=str,
DEPRECATED. Name of the rmsd function in the score file used to evaluate fitness of the alphafold predictions. Optional, requires stabilize_binder=True.
--rmsd_to_starting
default=None, type=str,
DEPRECATED. Name of the rmsd function in the score file and the path/filename to pdb for RMSD used to evaluate rmsd to the starting scaffold using a U-shaped potential.
--path_to_starting
default=None, type=str,
DEPRECATED. path/filename to pdb to pass to the scoring function for RMSD to starting.
The score functions are a way to generate a “score” from the AlphaFold2 result for each sequence of the optimization pool – and this score is used for ranking and filtering the sequences (so it is only the relative value of the score that matters). Each score function therefore takes in the list of results dictionaries (one for each AF2 prediction made for the sequence) and parses the different components such as the predicted structures in PDB form, pLDDT, PAE, etc. The score function should then return a final overall score for the sequence that can contain different weighted score components.
EvoPro includes a few functions that are prewritten to be called within your score function, that calculate different score metrics which may then be used as weighted components in the final overall score that is returned from your score function. For example, a function to calculate the average pLDDT over a predicted PDB (score_plddt_confidence) or to calculate the contacts at an interface, where each contact is weighted by the PAE of the interaction (score_contacts_pae_weighted). You can import these from evopro.score_funcs.score_funcs, as is done at the top of score_binder.py, or use your own functions instead. Important to know: the more negative scores are better, so we negate score terms that we want to maximize and keep positive the score terms that we want to minimize.
See below for an example score function with annotated code:
def score_overall(results, dsobj, contacts=None, distance_cutoffs=None):
#This is the primary scoring function that is called in the main code. The purpose of this
#function is to determine whether it is the complex prediction (with both binder and
#target) or the monomeric (just binder) prediction that is being evaluated and return the
#corresponding score. The main code will then pair the complex and monomer predictions and
#sum the scores from each.
from alphafold.common import protein
#The results here are a list of results dictionaries
#one for each AF2 prediction generated for the same design sequence
#so this number should match the number of items in af2_preds
print("Number of predictions being scored:", len(results))
#change binder chain here if target protein has more than one chain
binder_chain="B"
#add path and filename to pdb here if you want to calculate RMSD of binder to something
starting_pdb = None
score=[]
pdbs = []
#parsing through each dictionary and scoring them based on which prediction it is
for result in results:
#Generate the pdb from the alphafold output
pdb = protein.to_pdb(result['unrelaxed_protein'])
pdbs.append(pdb)
#Parse chains and residues from the pdb
#chains will look like [“A”, “B”] and residues like [“A1”, “A2”, … , “B1”, “B2”, …]
chains, residues, resindices = get_coordinates_pdb(pdb)
if len(chains)>1: #if we are scoring the complex
#Here, contacts and distance_cutoffs come as arguments from the main code
#(see more descriptions of both inside this function below)
score.append(score_binder_complex(result, dsobj, contacts, distance_cutoffs, binder_chain=binder_chain))
else:
#If the prediction has only one chain call the monomer scoring function.
score.append(score_binder_monomer(result, dsobj))
if starting_pdb:
score.append(score_binder_rmsd_to_starting(pdb, starting_pdb, dsobj=dsobj, binder_chain=binder_chain))
score.append(score_binder_rmsd(pdbs[0], pdbs[1], dsobj=dsobj, binder_chain=binder_chain))
#you can weight individual values here too
overall_score = sum([x[0] for x in score])
#Return values. Here, first term is the overall score to use for ranking and second
#term has the individual score components that will be printed out in the log file and used for plotting.
#NOTE: pdb, results MUST be returned and should always be the last 2 elements.
return overall_score, score, pdbs, results
def score_binder_complex(results, dsobj, contacts, distance_cutoffs, binder_chain="B"):
#This is the complex scoring function that is called from the primary score function.
#Here, contacts is a tuple containing three items which all come from user inputs:
#(interface_contacts, bonus_contacts, penalty_contacts)
#Interface contacts come from the flag --define_contact_area where the user defines
#which residues on the target protein are being targeted for binding.
#Bonus contacts come from the flag -- bonus_contacts (optional) where the user defines
#residues that are given a “bonus” if contacted by the binder.
#For this, we usually use a single residue in the middle of the target interface to help
#select for binders that are in the right place.
#Penalty contacts come from the flag -- penalize_contacts (optional) where the user defines
#residues that are given a “penalty” if contacted by the binder.
#Distance cutoffs also contains 3 elements representing the Angstrom cutoff for each
#of these types of contacts. The default is (4,4,8) and can be changed through the flags.
from alphafold.common import protein
pdb = protein.to_pdb(results['unrelaxed_protein'])
chains, residues, resindices = get_coordinates_pdb(pdb)
#setting defaults if no user input
if not contacts:
contacts=(None,None,None)
if not distance_cutoffs:
distance_cutoffs=(4,4,8)
#Get interface contacts on target protein
reslist1 = contacts[0]
#Get residues on binder (here, all of chain B) that can bind to the interface contacts
reslist2 = [x for x in residues.keys() if x.startswith(binder_chain)]
#Get list of interacting residues and PAE-weighted contact score
contact_list, contactscore = score_contacts_pae_weighted(results, pdb, reslist1, reslist2, dsobj=dsobj, first_only=False, dist=distance_cutoffs[0])
bonuses = 0
#Get bonus contacts on target protein
bonus_resids = contacts[1]
if bonus_resids:
bonus_contacts, bonus_contactscore = score_contacts_pae_weighted(results, pdb, bonus_resids, reslist2, dsobj=dsobj, first_only=False, dist=distance_cutoffs[1])
for contact in bonus_contacts:
if contact[0][0:1] == 'A' and int(contact[0][1:]) in bonus_resids:
bonuses += 1
print("bonus found at: " + str(contact[0]))
if contact[1][0:1] == 'A' and int(contact[1][1:]) in bonus_resids:
bonuses += 1
print("bonus found at: " + str(contact[1]))
#Give each bonus contact a score value of -3.
bonus = -bonuses * 3
penalties = 0
penalty_resids = contacts[2]
if penalty_resids:
penalty_contacts, penalty_contactscore = score_contacts_pae_weighted(results, pdb, penalty_resids, reslist2, dsobj=dsobj, first_only=False, dist=distance_cutoffs[2])
for contact in penalty_contacts:
if contact[0][0:1] == 'A' and int(contact[0][1:]) in penalty_resids:
penalties += 1
print("penalty found at: " + str(contact[0]))
if contact[1][0:1] == 'A' and int(contact[1][1:]) in penalty_resids:
penalties += 1
print("penalty found at: " + str(contact[1]))
#Give each penalty contact a score value of +3
penalty = penalties * 3
#Get the average PAE of interface contacts (pae_interaction)
num_contacts = len(contacts)
pae_per_contact = 0
if num_contacts > 0:
pae_per_contact = (70.0-(70.0*contactscore)/num_contacts)/2
#Calculate the weighted score to return
score = -contactscore + penalty + bonus
return score, (score, len(contacts), contactscore, pae_per_contact, bonus, penalty), contacts, pdb, results
def score_binder_monomer(results, dsobj):
#This is the monomer scoring function that is called from the primary score function.
from alphafold.common import protein
pdb = protein.to_pdb(results['unrelaxed_protein'])
#Parse chains and residues from the pdb
chains, residues, resindices = get_coordinates_pdb(pdb)
#Select residues to be included in average pLDDT score
#Here, we select all residues in the binder-only AF2 prediction
reslist2 = [x for x in residues.keys()]
confscore2 = score_plddt_confidence(results, reslist2, resindices, dsobj=dsobj, first_only=False)
#calculate overall score to be returned from this function
#We divide by 10 since the values are in generally the range of 80-100
#so this term does not dominate over the complex scores (in the 10s range)
score = -confscore2/10
return score, (score, confscore2), pdb, resultsAmrita Nallathambi - anallathambi@unc.edu
Since I am a grad student, this code may not be perfect. Please email me with any questions or concerns!