PPI2Text: Captioning Protein-Protein Interactions with Coordinate-Aligned Pair-Map Decoding

Fuente: arXiv
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Main Authors: Fei, Xiao, Carneiro, Sarah Almeida, Zhang, Yang, Petalidis, Lawrence P., Tsortos, Achilleas, Bouyioukos, Costas, Vazirgiannis, Michalis
Format: Preprint
Published: 2026
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author Fei, Xiao
Carneiro, Sarah Almeida
Zhang, Yang
Petalidis, Lawrence P.
Tsortos, Achilleas
Bouyioukos, Costas
Vazirgiannis, Michalis
author_facet Fei, Xiao
Carneiro, Sarah Almeida
Zhang, Yang
Petalidis, Lawrence P.
Tsortos, Achilleas
Bouyioukos, Costas
Vazirgiannis, Michalis
contents Protein-protein interaction (PPI) modeling has been widely studied as a binary or multi-label classification task. While emerging multimodal large language models (LLMs) can now describe single proteins, they remain unable to generate free-form descriptions of interactions between protein pairs. Moving beyond controlled vocabulary annotations, we propose to model PPI using free-text description, enabling richer expressiveness, improved interpretability, and better integration with literature knowledge base. We present PPI2Text, a multimodal LLM for free-form PPI captioning from amino acid sequences, that encodes each protein using ESM3 encoder, constructs a pair map from the two representations to capture interactions across all residue pairs, and autoregressively generates descriptions using a Qwen3 language decoder. We further introduce PaCo-RoPE, a coordinate-aligned positional encoding that aligns each axis of the pair grid with the residue positions of the corresponding protein. In addition, we release PPI2Text-Dataset, a 351k-pair corpus of free-form PPI descriptions aggregated from ten curated biological databases and further synthesized with Gemini under evidence-tiered prompting. PPI2Text consistently outperforms strong baselines across multiple ablation settings and evaluation protocols. It not only achieves higher scores on linguistic metrics against synthesized references, but also excels on factuality metrics, where an LLM-based judge evaluates outputs against raw biological evidence.
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id arxiv_https___arxiv_org_abs_2605_08924
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle PPI2Text: Captioning Protein-Protein Interactions with Coordinate-Aligned Pair-Map Decoding
Fei, Xiao
Carneiro, Sarah Almeida
Zhang, Yang
Petalidis, Lawrence P.
Tsortos, Achilleas
Bouyioukos, Costas
Vazirgiannis, Michalis
Computational Engineering, Finance, and Science
Protein-protein interaction (PPI) modeling has been widely studied as a binary or multi-label classification task. While emerging multimodal large language models (LLMs) can now describe single proteins, they remain unable to generate free-form descriptions of interactions between protein pairs. Moving beyond controlled vocabulary annotations, we propose to model PPI using free-text description, enabling richer expressiveness, improved interpretability, and better integration with literature knowledge base. We present PPI2Text, a multimodal LLM for free-form PPI captioning from amino acid sequences, that encodes each protein using ESM3 encoder, constructs a pair map from the two representations to capture interactions across all residue pairs, and autoregressively generates descriptions using a Qwen3 language decoder. We further introduce PaCo-RoPE, a coordinate-aligned positional encoding that aligns each axis of the pair grid with the residue positions of the corresponding protein. In addition, we release PPI2Text-Dataset, a 351k-pair corpus of free-form PPI descriptions aggregated from ten curated biological databases and further synthesized with Gemini under evidence-tiered prompting. PPI2Text consistently outperforms strong baselines across multiple ablation settings and evaluation protocols. It not only achieves higher scores on linguistic metrics against synthesized references, but also excels on factuality metrics, where an LLM-based judge evaluates outputs against raw biological evidence.
title PPI2Text: Captioning Protein-Protein Interactions with Coordinate-Aligned Pair-Map Decoding
topic Computational Engineering, Finance, and Science
url https://arxiv.org/abs/2605.08924