MolFM-Lite: Multi-Modal Molecular Property Prediction with Conformer Ensemble Attention and Cross-Modal Fusion
Organizations: Department of Computer Science and Engineering, University at Buffalo, Buffalo, NY, USA · Khoury College of Computer Sciences, Northeastern University, Boston, MA, USA · Department of Computer Science, Muffakham Jah College of Engineering and Technology, Hyderabad, India · Department of Computer Science and Artificial Intelligence, Muffakham Jah College of Engineering and Technology, Hyderabad, India
Abstract
Most machine learning models for molecular property prediction rely on a single molecular representation (either a sequence, a graph, or a 3D structure) and treat molecular geometry as static. We present MolFM-Lite, a multi-modal model that jointly encodes SELFIES sequences (1D), molecular graphs (2D), and conformer ensembles (3D) through cross-attention fusion, while conditioning predictions on experimental context via Feature-wise Linear Modulation (FiLM). Our main methodological contributions are: (1) a conformer ensemble attention mechanism that combines learnable attention with Boltzmann-weighted priors over multiple RDKit-generated conformers, capturing the thermodynamic distribution of molecular shapes; and (2) a cross-modal fusion layer where each modality can attend to others, enabling complementary information sharing. We evaluate on four MoleculeNet scaffold-split benchmarks using our model's own splits, and report all baselines re-evaluated under the same protocol. Comprehensive ablation studies across all four datasets confirm that each architectural component contributes independently, with tri-modal fusion providing 7-11% AUC improvement over single-modality baselines and conformer ensembles adding approximately 2% over single-conformer variants. Pre-training on ZINC250K (~250K molecules) using cross-modal contrastive and masked-atom objectives enables effective weight initialization at modest compute cost. We release all code, trained models, and data splits to support reproducibility.
Figures & tables
| Method | Modality | BBBP | BACE | Tox21 | Lipo |
|---|---|---|---|---|---|
| ChemBERTa ( Chithrananda et al., 2020 ) | 1D | 0.872 | 0.856 | 0.782 | 0.654 |
| MolBERT ( Fabian et al., 2020 ) | 1D | 0.868 | 0.849 | 0.776 | 0.668 |
| GIN ( Xu et al., 2019 ) | 2D | 0.871 | 0.861 | 0.779 | 0.668 |
| GROVER ( Rong et al., 2020 ) | 2D | 0.894 | 0.878 | 0.795 | 0.642 |
| SchNet ( Schütt et al., 2017 ) | 3D | 0.847 | 0.823 | 0.756 | 0.692 |
| GEM ( Fang et al., 2022 ) | 3D | 0.908 | 0.869 | 0.803 | 0.612 |
| Model Variant | AUC | |
|---|---|---|
| Full model | 0.956 | – |
| Modality ablations | ||
| 1D only (SELFIES) | 0.872 | 0.084 |
| 2D only (Graph) | 0.884 | 0.072 |
| 3D only (Conformers) | 0.847 | 0.109 |
| 1D + 2D (no 3D) | 0.912 | 0.044 |
| Model Variant | AUC | |
|---|---|---|
| Full model | 0.902 | – |
| 1D only | 0.856 | 0.046 |
| 2D only | 0.861 | 0.041 |
| 3D only | 0.823 | 0.079 |
| 1D + 2D (no 3D) | 0.874 | 0.028 |
| Single conformer ( ) | 0.887 | 0.015 |
| Model Variant | AUC | |
|---|---|---|
| Full model | 0.848 | – |
| 1D only | 0.782 | 0.066 |
| 2D only | 0.795 | 0.053 |
| 3D only | 0.756 | 0.092 |
| 1D + 2D (no 3D) | 0.821 | 0.027 |
| Single conformer ( ) | 0.839 | 0.009 |
| Model Variant | RMSE | |
|---|---|---|
| Full model | 0.570 | – |
| 1D only | 0.654 | 0.084 |
| 2D only | 0.642 | 0.072 |
| 3D only | 0.692 | 0.122 |
| 1D + 2D (no 3D) | 0.598 | 0.028 |
| Single conformer ( ) | 0.583 | 0.013 |
| Task | AUC | Task | AUC |
|---|---|---|---|
| NR-AR | 0.812 | SR-ARE | 0.806 |
| NR-AR-LBD | 0.849 | SR-ATAD5 | 0.857 |
| NR-AhR | 0.888 | SR-HSE | 0.847 |
| NR-Aromatase | 0.909 | SR-MMP | 0.909 |
| NR-ER | 0.734 | SR-p53 | 0.864 |
| NR-ER-LBD | 0.798 |
| Phase | GPU Hours | Cost (USD) |
|---|---|---|
| Pre-training (ZINC250K, 30 ep) | 8.0 | $4.21 |
| Fine-tuning BBBP (3 seeds) | 3.0 | $1.58 |
| Fine-tuning BACE (3 seeds) | 3.0 | $1.58 |
| Fine-tuning Tox21 (3 seeds) | 4.5 | $2.37 |
| Fine-tuning Lipophilicity (3 seeds) | 3.0 | $1.58 |
| Ablation studies (all datasets) | 40.0 | $21.04 |
Appendix figures & tables1 asset
Supplementary material from the paper’s appendix.
Appendix
| Component | Hyperparameter | Value |
| Pre-training | Epochs | 30 |
| Batch size | 64 | |
| Learning rate | ||
| Weight decay | ||
| Contrastive temperature | 0.07 | |
| Warmup steps | 1,000 |
Molecular Property Prediction
Molecular property prediction estimates chemical, physical, and biological properties from molecular structure and context.
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