Paraplume is a sequence-based paratope prediction method. It predicts which amino acids in an antibody sequence are likely to interact with an antigen during binding. Concretely, given an amino acid sequence, the model returns a probability for each residue indicating the likelihood of antigen interaction. Go check out our paper to see how Paraplume can be used to study antibody evolution/function !

---

📖 HOW IT WORKS

Paraplume uses supervised learning and involves three main steps:

1. Labelling: Antibody sequences are annotated with paratope labels using structural data from SAbDab.

2. Sequence representation: Each amino acid is embedded into a high-dimensional vector using Protein Language Model (PLM) embeddings.

3. Model training: A Multi-Layer Perceptron (MLP) is trained to minimize Binary Cross-Entropy Loss, using PLM embeddings as inputs and paratope labels as targets.

The full workflow of Paraplume is summarized Figure B below:

---

⚙️ INSTALLATION

It is available on PyPI and can be installed through pip.

pip install paraplume

We recommend installing it in a virtual environment with python >= 3.10.

---

💻 COMMAND LINE

We provide several commands to use the model as inference with the default weights or retrain the model with a custom dataset. All commands can be run with cpu or gpu, if available (cf gpu option).

paraplume-infer provides two commands, one to infer the paratope from a unique sequence (seq-to-paratope) and another from a batch of sequences in the form of a csv file (file-to-paratope).

paraplume-infer COMMAND [OPTIONS][ARGS] ...

By default the model used is trained using the 'expanded' dataset from the Paragraph paper, that we divided in 1000 sequences for the training set and 85 sequences for the validation and available in ./datasets/. PDB 4FQI was excluded from the train and validation sets as we analyze variants of this antibody in our paper using the trained model.

However we also provide the possibility to use a custom model for inference. To train your custom model you will need to run three commands: paraplume-build-dictionary to generate labels, paraplume-create-embeddings to create PLM embeddings for your desired training dataset, and paraplume-train to train the model.

After training the model on your custom dataset, the model is saved in a folder whose path can be given to the inference commands as a --custom-model option.

📋 Commands

1. paraplume-infer seq-to-paratope

Predict paratope directly from amino acid sequences provided as command line arguments.

Usage

paraplume-infer seq-to-paratope [OPTIONS]

Options

Option	Type	Default	Description
-h, --heavy-chain	TEXT	-	Heavy chain amino acid sequence
-l, --light-chain	TEXT	-	Light chain amino acid sequence
--custom-model	PATH	None	Path to custom trained model folder
--gpu	INT	0	Choose index of GPU device to use if multiple GPUs available. By default it's the first one (index 0). -1 forces cpu usage. If no GPU is available, CPU is used
--large/--small	flag	--large	Use default Paraplume which uses the 6 PLMs AbLang2,Antiberty,ESM,ProtT5,IgT5 and IgBert (--large) or the smallest version using only ESM-2 embeddings (--small)

Examples

Both chains:

paraplume-infer seq-to-paratope \
  -h QAYLQQSGAELVKPGASVKMSCKASDYTFTNYNMHWIKQTPGQGLEWIGAIYPGNGDTSYNQKFKGKATLTADKSSSTAYMQLSSLTSEDSAVYYCASLGSSYFDYWGQGTTLTVSS \
  -l EIVLTQSPTTMAASPGEKITITCSARSSISSNYLHWYQQKPGFSPKLLIYRTSNLASGVPSRFSGSGSGTSYSLTIGTMEAEDVATYYCHQGSNLPFTFGSGTKLEIK

Heavy chain only:

paraplume-infer seq-to-paratope \
  -h QAYLQQSGAELVKPGASVKMSCKASDYTFTNYNMHWIKQTPGQGLEWIGAIYPGNGDTSYNQKFKGKATLTADKSSSTAYMQLSSLTSEDSAVYYCASLGSSYFDYWGQGTTLTVSS

Light chain only:

paraplume-infer seq-to-paratope \
  -l EIVLTQSPTTMAASPGEKITITCSARSSISSNYLHWYQQKPGFSPKLLIYRTSNLASGVPSRFSGSGSGTSYSLTIGTMEAEDVATYYCHQGSNLPFTFGSGTKLEIK

2. paraplume-infer file-to-paratope

Predict paratope from sequences stored in a CSV file.

Usage

paraplume-infer file-to-paratope [OPTIONS] FILE_PATH

Arguments

Argument	Type	Required	Description
FILE_PATH	PATH	✓	Path to input CSV file

Options

Option	Type	Default	Description
--custom-model	PATH	None	Path to custom trained model folder
--name	TEXT	paratope_	Prefix for output file
--gpu	INT	0	Choose index of GPU device to use if multiple GPUs available. By default it's the first one (index 0). -1 forces cpu usage. If no GPU is available, CPU is used
--result-folder, -r	PATH	None	Folder path where to save the results. If not passed the result is saved in the input data folder
--emb-proc-size	INT	100	Embedding batch size for memory management
--compute-sequence-embeddings	flag	False	Compute both paratope and classical sequence embeddings for each sequence and each of the 6 PLMs AbLang2, Antiberty, ESM, ProtT5, IgT5 and IgBert. Only possible when using the default trained_models/large
--single-chain	flag	False	Process single chain sequences
--large/--small	flag	--large	Use default Paraplume which uses the 6 PLMs AbLang2,Antiberty,ESM,ProtT5,IgT5 and IgBert (--large) or the smallest version using only ESM-2 embeddings (--small)
│ --compute-shap	flag	False	Compute SHAP importance analysis and generate visualizations. A folder 'shap_results' will be created with a plot inside for each sequence.

Examples

Paired chains:

paraplume-infer file-to-paratope ./tutorial/paired.csv

Heavy chain only:

paraplume-infer file-to-paratope ./tutorial/heavy.csv --single-chain

Light chain only:

paraplume-infer file-to-paratope ./tutorial/light.csv --single-chain

Sample input files are available in the tutorial folder.

Input

Your CSV file must include these columns (any additional column is fine):

For paired chains (default):

sequence_heavy	sequence_light
QAYLQQSGAELVKPGASVKMSCKASDYTFTNYNMHWIKQTPGQGLEWIGAIYPGNGDTSYNQKFKGKATLTADKSSSTAYMQLSSLTSEDSAVYYCASLGSSYFDYWGQGTTLTVSS	EIVLTQSPTTMAASPGEKITITCSARSSISSNYLHWYQQKPGFSPKLLIYRTSNLASGVPSRFSGSGSGTSYSLTIGTMEAEDVATYYCHQGSNLPFTFGSGTKLEIK
EVQLVESGGGLVQPGGSLRLSCAASGFTFSRYAMSWVRQAPGKGLEWVSVISSGGSYTYYADSVKGRFTISRDNAKNSLYLQMNSLRAEDTAVYYCAKDREYRYYYYGMDVWGQGTTVTVSS	DIQMTQSPSSLSASVGDRVTITCRASQGISSWLAWYQQKPGKAPKLLIYDASSLESGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYGSSPPYTFGQGTKLEIK

For single heavy chain (use --single-chain):

sequence_heavy	sequence_light
QAYLQQSGAELVKPGASVKMSCKASDYTFTNYNMHWIKQTPGQGLEWIGAIYPGNGDTSYNQKFKGKATLTADKSSSTAYMQLSSLTSEDSAVYYCASLGSSYFDYWGQGTTLTVSS
EVQLVESGGGLVQPGGSLRLSCAASGFTFSRYAMSWVRQAPGKGLEWVSVISSGGSYTYYADSVKGRFTISRDNAKNSLYLQMNSLRAEDTAVYYCAKDREYRYYYYGMDVWGQGTTVTVSS

For single light chain (use --single-chain):

sequence_heavy	sequence_light
	EIVLTQSPTTMAASPGEKITITCSARSSISSNYLHWYQQKPGFSPKLLIYRTSNLASGVPSRFSGSGSGTSYSLTIGTMEAEDVATYYCHQGSNLPFTFGSGTKLEIK
	DIQMTQSPSSLSASVGDRVTITCRASQGISSWLAWYQQKPGKAPKLLIYDASSLESGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYGSSPPYTFGQGTKLEIK

Output

Creates a pickle file (e.g., ./tutorial/paratope_paired.pkl) containing:

• model_prediction_heavy - Paratope predictions for heavy chains
• model_prediction_light - Paratope predictions for light chains

Reading results:

import pandas as pd
predictions = pd.read_pickle("./tutorial/paratope_paired.pkl")
print(predictions.head())

3. paraplume-build-dictionary

Create dataset to train the neural network. Sequences and labels are saved in a .json file, and LPLM embeddings are saved in a .pt file.

Usage

paraplume-build-dictionary [OPTIONS] CSV_FILE_PATH PDB_FOLDER_PATH

Arguments

Argument	Type	Required	Description
CSV_FILE_PATH	PATH	✓	Path of csv file to use for pdb list
PDB_FOLDER_PATH	PATH	✓	Pdb path for ground truth labeling

Options

Option	Type	Default	Description
--result-folder, -r	PATH	result	Where to save results
--help	flag	-	Show this message and exit

Example

paraplume-build-dictionary ./tutorial/custom_train_set.csv pdb_folder -r training_data

Input

custom_train_set.csv contains information about the PDB files used for training and has the following format:

pdb	Lchain	Hchain	antigen_chain
1ahw	D	E	F
1bj1	L	H	W
1ce1	L	H	P

Column descriptions:

• pdb: PDB code of the antibody-antigen complex (should be available in pdb_folder as pdb_folder/pdb_code.pdb)
• Lchain: Light chain identifier used to label the paratope
• Hchain: Heavy chain identifier used to label the paratope
• antigen_chain: Antigen chain identifier used to label the paratope

Output

Creates a folder with the same name as the CSV file (e.g., custom_train_set) inside the result folder (training_data), which contains dict.json: Sequences and labels for each structure

4. paraplume-create-embeddings

Generate PLM embeddings from a dictionary file created by paraplume-build-dictionary and saves them in the folder of the dictionary.

Usage

paraplume-create-embeddings [OPTIONS] DICT_PATH

Arguments

Argument	Type	Required	Description
DICT_PATH	PATH	✓	Path to the folder containing dict.json

Options

Option	Type	Default	Description
--emb-proc-size	INTEGER	100	Chunk size for creating embeddings to avoid memory explosion. Optimal value depends on your computer
--gpu	INTEGER	0	Choose index of GPU device to use if multiple GPUs available. By default it's the first one (index 0). -1 forces cpu usage. If no GPU is available, CPU is used
--single-chain	flag	False	Generate embeddings using LLMs on single chain mode, which slightly increases performance
--help	flag	-	Show this message and exit

Example

paraplume-create-embeddings ./training_data/custom_train_set/dict.json \
  --gpu 0 \
  --emb-proc-size 50 \
  --single-chain

Input

Path of dict.json: Dictionary file created by paraplume-build-dictionary with sequences and labels

Output

Creates multiple embedding files in the same folder as dict.json:

• ablang2_embeddings.pt: AbLang2 model embeddings
• igbert_embeddings.pt: IgBERT model embeddings
• igT5_embeddings.pt: IgT5 model embeddings
• esm_embeddings.pt: ESM model embeddings
• antiberty_embeddings.pt: AntiBERTy model embeddings
• prot-t5_embeddings.pt: ProtT5 model embeddings

5. paraplume-train

Train the model given provided parameters and data.

Usage

paraplume-train [OPTIONS] TRAIN_FOLDER_PATH VAL_FOLDER_PATH

Arguments

Argument	Type	Required	Description
TRAIN_FOLDER_PATH	PATH	✓	Path of train folder
VAL_FOLDER_PATH	PATH	✓	Path of val folder

Options

Option	Type	Default	Description
--lr	FLOAT	0.001	Learning rate to use for training
--n_epochs, -n	INTEGER	1	Number of epochs to use for training
--result-folder, -r	PATH	result	Where to save results
--pos-weight	FLOAT	1	Weight to give to positive labels
--batch-size, -bs	INTEGER	10	Batch size
--mask-prob	FLOAT	0	Probability with which to mask each embedding coefficient
--dropouts	TEXT	0	Dropout probabilities for each hidden layer, separated by commas. Example '0.3,0.3'
--dims	TEXT	1000	Dimensions of hidden layers. Separated by commas. Example '100,100'
--override	flag	False	Override results
--seed	INTEGER	0	Seed to use for training
--l2-pen	FLOAT	0	L2 penalty to use for the model weights
--patience	INTEGER	0	Patience to use for early stopping. 0 means no early stopping
--emb-models	TEXT	all	LLM embedding models to use, separated by commas. LLMs should be in 'ablang2','igbert','igT5','esm','antiberty','prot-t5','all'. Example 'igT5,esm'
--gpu	INTEGER	0	Choose index of GPU device to use if multiple GPUs available. By default it's the first one (index 0). -1 forces cpu usage. If no GPU is available, CPU is used

Example

paraplume-train training_data/custom_train_set training_data/custom_val_set \
  --lr 0.001 \
  -n 50 \
  -r training_results \
  --batch-size 32 \
  --dims 512,256 \
  --dropouts 0.2,0.1 \
  --patience 5 \
  --emb-models igT5,esm \
  --gpu 0

Input

The two arguments (training_data/custom_train_set and training_data/custom_val_set in the example) are paths of folders created by the previous paraplume-build-dictionary command.

Output

Model weights and training parameters are saved in a folder specified by the -r option (training_results in the example, results by default).

The resulting trained model can then be used at inference by passing the output folder path as the --custom-model argument of the inference commands (see inference command lines).

---

🚀 TUTORIALS

Command Line Tutorial

If you want to use the default model with the already trained weights, just install the package and run paraplume-infer file-to-paratope ./tutorial/paired.csv and the result will be available as paratope_paired.pkl in the same tutorial folder.

If you want to train and use your custom model via command line, follow the 4 steps below.

Step 0: Set up

• Clone repository
• Make sure you are in Paraplume.
• Install the package in your favorite virtual environment with pip install paraplume
• Download PDB files from SabDab using IMGT format and save them in ./all_structures/imgt.

Step 1: Create training and validation datasets from CSVs

paraplume-build-dictionary ./tutorial/custom_train_set.csv ./all_structures/imgt -r custom_folder

followed by

paraplume-create-embeddings ./custom_folder/custom_train_set/dict.json \
  --gpu 0 \
  --emb-proc-size 50

The folder custom_folder will be created. Inside this folder the folder custom_train_set is created in which there are two files, dict.json for the sequences and labels, and emebddings for each of the 6 PLM. Repeat for the validation set (used for early stopping):

paraplume-build-dictionary ./tutorial/custom_val_set.csv ./all_structures/imgt -r custom_folder

followed by

paraplume-create-embeddings ./custom_folder/custom_val_set/dict.json \
  --gpu 0 \
  --emb-proc-size 50

Step 2: Train the model

paraplume-train ./custom_folder/custom_train_set ./custom_folder/custom_val_set \
  --lr 0.001 \
  -n 50 \
  --batch-size 8 \
  --dims 512,256 \
  --dropouts 0.2,0.1 \
  --patience 5 \
  --emb-models igT5,esm \
  --gpu 0 \
  -r ./custom_folder

This will save training results in custom_folder. checkpoint.pt contains the weights of the model, summary_dict.json contains the parameters used for training, and summary_plot.png some plots showing the training process.

Step 3: Use the trained custom model for inference

After training, your custom model will be saved in the results folder and can be used with inference commands using the --custom-model option.

paraplume-infer file-to-paratope ./tutorial/paired.csv --custom-model ./custom_folder

And the result is available as paratope_paired.pkl in the tutorial folder !!

Python Tutorial

A comprehensive Python tutorial for default inference usage (using the already trained weights) with examples is available in the tutorial folder.

If you want to use to train and use your custom model, follow the command line tutorial. Don't hesitate to contact me if you need help gabrielathenes@gmail.com.

---

📊 BENCHMARK

The benchmark was conducted using Paraplume v1.0.0. The final model configuration used a learning rate of (1 \times 10^{-5}), a batch size of 16 sequences, and the ADAM optimizer with an L2 regularization weight of (1 \times 10^{-5}). The MLP architecture consisted of three hidden layers with widths of 2000, 1000, and 500. A summary of the explored hyperparameter ranges and the selected values is provided in Table S4 of the paper.

All experiments were performed on a workstation equipped with two NVIDIA RTX 5000 Ada GPUs (32 GB VRAM each). Models were trained and evaluated using random seeds 1 through 16, and all reported results correspond to averages across these seeds.

All scripts and generated data are publicly available on the Zenodo repository.

---

🔍 INTERPRETABILITY

Predictions and PLM importance over residues can be visualized with the --compute-shap option of paraplume-infer file-to-paratope.

---

⚡ QUICK START

1. Install: pip install paraplume
2. Single sequence: paraplume-infer seq-to-paratope -h YOUR_HEAVY_CHAIN -l YOUR_LIGHT_CHAIN
3. File batch: paraplume-infer file-to-paratope your_file.csv

For detailed usage, expand the sections above! 👆

🛠️ Troubleshooting & Notes

• During the first inference, Paraplume will automatically download PLM weights inside your virtual environment. This step may take 10–15 minutes, depending on connection and hardware.
• This download only happens once. Future runs will start right away.
• If the full model is too heavy for your system, try the light version by adding --small, which uses only ESM.

Common Issues

AbLang2 Download Error

If you encounter the following error:

CalledProcessError: Command '['tar', '-zxvf', 'YOURFOLDER/tmp.tar.gz',
'-C', 'YOURFOLDER']' returned non-zero exit status 2.

This occurs because AbLang2 failed to download its model weights from the Zenodo server.

Fix: Download the weights manually:

TARGET=YOURFOLDER
mkdir -p "$TARGET"
curl -L "https://zenodo.org/records/10185169/files/ablang2-weights.tar.gz" | tar -xz -C "$TARGET"

Replace YOURFOLDER with the actual path shown in your error message. After running these commands, Paraplume should work correctly.

📧 Contact

Any issues or questions should be addressed to us at gabrielathenes@gmail.com.