Foundation
Energy-based latent representation learning
Pre-trained protein language models such as ESM-2 and ProtT5-XL capture rich co-evolutionary dependencies, but their latent spaces are not organised by free energy and do not encode the directed, downhill nature of folding trajectories.
PathFold adapts these embeddings with an energy-informed contrastive learning scheme grounded in energy-landscape theory. Every conformation is described by residue-resolved geometric descriptors (contact maps, torsion angles, solvent exposure, secondary-structure states). A free-energy surrogate, the fraction of native contacts Q combined with a statistical contact potential, assigns a scalar energy to each conformation. Conformations with similar Q form positive pairs, distant ones negative pairs, and an InfoNCE loss in the residue-resolved embedding space pulls energetically adjacent conformations together.
The result is a thermodynamically ordered latent manifold in which neighbouring points represent plausible sequential steps along a folding pathway, the geometric foundation for PathFold-P. A lightweight two-layer MLP projects PLM embeddings (ESM-2 650M: 1280 dims; ProtT5-XL: 1024 dims) into this energy-aligned space.