arXiv Machine Learning

STAR-VAE: A Scalable Latent-Variable Transformer for Controllable Molecular Generation

STAR-VAE is a Transformer-based variational autoencoder that uses SELFIES encoding and a bidirectional encoder with an autoregressive decoder pretrained on 79 million PubChem molecules. It incorporates a property signal to jointly condition the prior, posterior, and decoder, and employs LoRA adapters for fine‑tuning on small datasets without altering the backbone. The model achieves 100 % validity and near‑perfect novelty in MOSES sampling, low KL divergence on several GuacaMol descriptors, strong synthetic‑accessibility conditioning, and effective docking‑score control across multiple protein targets, while also enabling scaffold recovery and diverse label‑conditioned generation on ChEMBL targets.

arXiv Machine Learning
1d ago

StabilityArc: Decoding Protein Sequence Embeddings into Generalizable Stability Landscapes

StabilityArc is a method that decodes protein sequence embeddings into generalizable stability landscapes. It uses a shared RoPE transformer to map frozen ESMC-600M residue representations into an Lx20 matrix of substitution effects, with a symmetric, contact-aware residual to predict epistasis. In extensive leave-one-protein-out tests on 134,794 ProteinGym variants, StabilityArc achieves a Spearman correlation of 0.7134, surpassing the best zero‑shot baseline, and further improves Kermut’s performance when used as a prior.

By Aaron L. Feller, Andrew D. Ellington, Claus O. Wilke
arXiv Machine Learning
Sep 4

SimpleDesign: A Joint Model for Protein Sequence and Structure Codesign

SimpleDesign is a single-stage, end-to-end model for joint protein sequence and structure design that eliminates the need for multi-stage training. It combines discrete cross-entropy for sequences with a regression objective for structures, using a Mixture-of-Transformer architecture to handle modality-specific processing while maintaining global self-attention. Trained on over 2 million sequence-structure pairs, SimpleDesign achieves strong performance on co-design and unconditional generation benchmarks.

By Jiarui Lu, Yuyang Wang, Yizhe Zhang, Jiatao Gu, Navdeep Jaitly, Joshua M. Susskind, Miguel \'Angel Bautista
arXiv Machine Learning
1d ago

Analysis of Quantized and Efficiently Adapted Protein Language Models

The study evaluates 4‑bit quantization and low‑rank adapter fine‑tuning (QLoRA) on several large protein language models, finding that many model‑task pairs retain over 90% of full fine‑tuning performance while achieving up to 90% GPU memory savings. QLoRA preserves early‑layer representations and induces task‑specific changes in later layers, closely resembling full fine‑tuning with smaller representational shifts. For generative models, 4‑bit quantization largely maintains structural and sequence‑level properties, though token‑level analysis reveals model‑dependent changes in autoregressive output distributions.

By Ilan Yaniv Zeisler, Sebastian Clancy, Pouriya Bayat, Saaim Raad, Ivan Kraskov, Matthew Xie, Vivian White, Spencer Perkins, Serena Singh, Sepehr Bayat, Keith Pardee
arXiv Machine Learning
1d ago

A Large Scale Investigation of Scaling Limits in Chemical Language Models

The paper reports a large-scale, compute-controlled study of Chemical Language Models (CLMs) involving over 30,000 experiments across different molecular representations, tokenizations, model sizes, datasets, and architectures. It finds clear scaling trends in pretraining loss but shows that these improvements do not translate into proportional gains in goal-directed molecular design, with chemical syntax saturating early while semantic properties develop more slowly. The authors release a new suite of models, NovoMolGen, that achieves state-of-the-art results in drug discovery tasks, highlighting a disconnect between representation learning and downstream design and calling for new pretraining paradigms that target chemical semantics.

By Roshan Balaji, Kamran Chitsaz, Quentin Fournier, Nirav Pravinbhai Bhatt, Sarath Chandar