Organizations: PsiDagger, San Diego, CA · Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA · Department of Chemistry and The PULSE Institute, Stanford University, Stanford, CA · SLAC National Accelerator Laboratory, Menlo Park, CA
The classic paradigm of structural biology is that the sequence of a biomolecule (protein, nucleic acid, lipid, etc) determines its conformation (shape) which determines its biological function. Protein folding programs like AlphaFold address this paradigm by predicting the single best conformation given a sequence that defines the molecule. However, biomolecules are not static structures, and their conformational ensemble determines their function. We present the Polyformer -- a generative framework for thermodynamic modeling of polymeric molecules. Given the sequence and temperature (or another thermodynamic variable), the Polyformer generates conformations faithful to the molecule's thermodynamic conformational ensemble. It is the first generative model that solves three problems simultaneously: how does a molecule fold, what is its conformational ensemble, and how does the conformational ensemble change as we change physical temperature. As a concrete test case, we apply Polyformer to protein domains with 50-111 residues and report good agreement of model predictions to Molecular Dynamics (MD) trajectories.
Figures & tables
Figure 1: Polyformer is a DiT conditioned on molecular sequence and temperature that generates conformation ensembles of protein backbones in a temperature-dependent way.
Figure 2: Comparison of Molecular Dynamics and Polyformer sampled conformation ensembles for domain 1g2rA00. Best matching pair of conformations is highlighted. The ensembles of conformations sampled by Polyformer are quite similar to Molecular Dynamics across all five temperatures.
Figure 3: Comparison of Molecular Dynamics and Polyformer sampled conformation ensemble for domain 1g2rA00. (a) Ramachandran plots comparing the distribution of ψ and ϕ dihedral angles. (b) RMSF plots comparing fluctuations along the back bone. (c) Plots comparing distributions of Rg . Across all three metrics, polyformer matches molecular dynamics pretty well.
Figure 4: Comparison of mean (solid points) and standard deviation (error bars) of Rg obtained by mdCATH and Polyformer ensemble sampling of domain lg2A00, showing good agreement.
Figure 5: Comparison of mean Rg obtained by mdCATH and Polformer ensemble sampling across all domains in the testing set and all temperatures in mdCATH dataset. The plots show good, but imperfect correlation.
Appendix figures & tables9 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 6: Comparison of Molecular Dynamics and Polyformer sampled conformation ensembles, same as Fig. 2 but for domain 3g0vA00.
Figure 7: Quantitative comparison of Polyformer and Molecular Dynamics sampled conformation ensemble, same as Fig. 3 but for domain 3g0vA00.
Figure 8: Performance of Polyformer without ESM-2 embedding. Compare with Fig. 2 in the main text.
Figure 9: Performance of Polyformer without ESM-2 embedding on domain 1g2rA00. Compare with Fig. 3 in the main text.
Figure 10: Performance of Polyformer without ESM-2 embedding on domain 3g0vA00. Compare with Fig. 7 in the appendix.
Figure 11: Performance of Polyformer without ESM-2 embedding. Compare with Fig. 5 in the main text.
Figure 12: Performance of SimplFold. Compare with Fig. 2 in the main text. Because SimpleFold tends to predict one dominant conformation, we have not highlighted the matching pair in the SimpleFold panel. For both domains, SimpleFold predicted two structures that did not match the other 298 strcutures and appear as thinner lines.
Figure 13: Performance of SimpleFold. Compare with Fig. 3 in the main text.
Figure 14: CDF of inverse of the learned reciprocal vectors (orange) and PDF of the C α -C α distances shaded blue. Observe that most of the inverse reciprocal vector magnitudes span the range of C α -C α distance.
All-atom generative modeling of 3D biomolecular complexes has emerged as the dominant paradigm for predicting the structure of proteins and protein-ligand systems. Generating structures at the atomic level of fidelity, however, typically requires expensive iterative diffusion rollouts, making both conventional deployment and inference-time search techniques computationally costly. In this paper, we introduce the Denoiser Cofolding All-Atom Flowmap (DeCAF) framework for distilling state-of-the-art all-atom cofolding models into all-atom flow maps that produce high-quality samples in only a few inference steps. We build DeCAF on a denoiser-based formulation of flow maps with endpoint losses that naturally support SE(3) rigid alignment, which we show is critical for training accurate models. We further derive a simple change of variables that lets DeCAF operate in the σ-space noise schedule of EDM-style architectures, enabling direct distillation from pretrained cofolding diffusion models. Equipped with DeCAF's flowmap lookahead, we introduce a purpose-built inference-time framework that improves sampling through reward-guided search. Empirically, DeCAF-Boltz statistically improves over Boltz-1x in both accuracy (RMSD) and physical validity scores of protein-ligand poses at strict NFE budgets on the challenging Runs N' Poses, while also showing a more optimal Pareto frontier across all inference compute budgets on PoseBusters. Distilling the state-of-the-art Pearl cofolding model, DeCAF-Pearl outperforms diffusion-based cofolding models and matches its teacher on success rate while using 5x fewer NFEs. We release our code at https://github.com/genesistherapeutics/decaf.
Gianluca Scarpellini, Ron Shprints, Peter Holderrieth +7
1Genesis Molecular AI · Massachusetts Institute of Technology · Carnegie Mellon University +2
Models from the AlphaFold (AF) family reliably predict one dominant conformation for most well-ordered proteins but struggle to capture biologically relevant alternate states. Several efforts have focused on eliciting greater conformational variability through ad hoc inference-time perturbations of AF models or their inputs. Despite their progress, these approaches remain inefficient and fail to consistently recover major conformational modes. Here, we investigate both the optimal location and manner-of-operation for perturbing latent representations in the AF3 architecture. We distill our findings in ConforNets: channel-wise affine transforms of the pre-Pairformer pair latents. Unlike previous methods, ConforNets globally modulate AF3 representations, making them reusable across proteins. On unsupervised generation of alternate states, ConforNets achieve state-of-the-art success rates on all existing multi-state benchmarks. On the novel supervised task of conformational transfer, ConforNets trained on one source protein can induce a conserved conformational change across a protein family. Collectively, these results introduce a mechanism for conformational control in AF3-based models.
Minji Lee, Colin Kalicki, Minkyu Jeon +3
Department of Computer Science, Columbia University, NY, USA · Department of Systems Biology, Columbia University, NY, USA · Department of Computer Science, Princeton University, Princeton, NJ, USA
Molecular graph encoding often relies on a single, static structure, ignoring the thermodynamic ensemble of molecules that are present in solution. Here, we introduce EnsembleEGNN, a foundation model that encodes structural ensembles by processing individual conformers through shared equivariant graph neural network layers, pooled with a set attention block, to make property predictions from the whole ensemble. Pretrained on the CREMP cyclic peptide dataset using multi-task self-supervision, the model is trained to encode the conformational variability of each molecule. When predicting membrane permeability from the CycPeptMPDB benchmark, EnsembleEGNN achieves an R2 of 0.477 under random cross-validation, outperforming a sequence-only BERT baseline (R2=0.439). This representation advantage persists under rigorous out-of-distribution Butina splits (R2=0.401 versus 0.354). Finally, a hybrid architecture co-training EnsembleEGNN with the BERT model achieves the highest overall accuracy across both random (R2=0.538) and structural holdout evaluations (R2=0.444). These results demonstrate that encoding conformational ensembles into latent representations improves predictions for properties governed by thermodynamics.
Aaron L. Feller, Kris Deibler, Maxim Secor
Interdisciplinary Life Sciences, University of Texas at Austin, Austin, TX. · Molecular AI, Novo Nordisk, Lexington, MA.