Unlocking Protein Secrets: How AI is Learning to Use Scientific Tools

Author: Denis Avetisyan


A new approach combines the power of large language models with computational biology tools to dramatically improve our understanding of protein function.

The system employs an interleaved reasoning pipeline, leveraging tool calls to effectively dissect and understand protein function.
The system employs an interleaved reasoning pipeline, leveraging tool calls to effectively dissect and understand protein function.

This review details PFUA, a tool-augmented agent that leverages interleaved tool-call reasoning to overcome the limitations of text-only approaches in bioinformatics and facilitate cold-start reasoning for protein sequence analysis.

While large language models excel at reasoning in symbolic domains, directly applying these techniques to complex scientific problems like protein function prediction proves surprisingly ineffective, often reinforcing superficial patterns rather than biological understanding. Our work, ‘Interleaved Tool-Call Reasoning for Protein Function Understanding’, addresses this limitation by introducing PFUA, a tool-augmented agent that synergistically combines LLMs with specialized bioinformatics tools for verifiable, knowledge-grounded reasoning. This approach consistently outperforms text-only models-achieving an average performance improvement of 103% across multiple benchmarks-by prioritizing external biological priors over purely internal inference. Could this paradigm of interleaved tool-call reasoning unlock deeper insights across other knowledge-intensive scientific disciplines?


Navigating the Complexity of Protein Function

The prediction of protein function represents a persistent bottleneck in modern computational biology, largely due to the inherent complexity of biological systems. Proteins don’t operate in isolation; their roles are deeply intertwined with myriad interactions – forming complexes, participating in metabolic pathways, and responding to diverse cellular signals. This interconnectedness creates a web of dependencies that traditional computational methods struggle to fully capture. Existing approaches often simplify these relationships, treating proteins as discrete entities with singular functions, which overlooks the plasticity and adaptability characteristic of living organisms. Consequently, accurately forecasting a protein’s role requires navigating a landscape of probabilistic interactions and contextual dependencies – a task demanding increasingly sophisticated analytical tools and a shift away from purely reductionist models.

Traditional approaches to deciphering protein function frequently depend on symbolic reasoning – essentially, identifying known patterns and applying pre-defined rules. However, this method often falls short when confronted with the inherent complexity of biological data. Proteins rarely operate in isolation; their functions are deeply intertwined with a multitude of interactions, post-translational modifications, and environmental factors. Symbolic reasoning struggles to adequately represent these nuanced relationships, treating them as discrete categories rather than continuous variables. Consequently, predictions based solely on these methods can oversimplify biological reality, overlooking subtle but critical details that determine a protein’s actual role within a living system. The limitations of this approach underscore the need for computational strategies capable of capturing the full spectrum of biological context and complexity inherent in protein data.

Traditional methods of protein function prediction are increasingly challenged by the sheer volume of biological data and the intricate web of relationships within it. Existing computational approaches often hit scaling limitations, struggling to efficiently analyze the exponentially growing datasets generated by modern genomics and proteomics. Furthermore, these methods frequently fail to fully incorporate the wealth of biological knowledge – including experimental data, literature, and evolutionary information – that could significantly improve prediction accuracy. Consequently, researchers are actively pursuing innovative strategies, such as machine learning and knowledge graphs, to effectively leverage this vast biological knowledge and overcome the computational bottlenecks hindering progress in understanding protein function and its role in complex biological systems.

Performance on the Mol-Instructions dataset demonstrates that utilizing <span class="katex-eq" data-katex-display="false">	ext{DeepSeek-Reasoner}</span>, <span class="katex-eq" data-katex-display="false">	ext{Kimi-K2}</span>, and <span class="katex-eq" data-katex-display="false">	ext{Qwen3-Max}</span> as backbones yields competitive ROUGE-1 and ROUGE-L scores across protein-oriented tasks, including function, catalytic activity, domain/motif recognition, and descriptive text generation (Fang et al., 2024).
Performance on the Mol-Instructions dataset demonstrates that utilizing ext{DeepSeek-Reasoner}, ext{Kimi-K2}, and ext{Qwen3-Max} as backbones yields competitive ROUGE-1 and ROUGE-L scores across protein-oriented tasks, including function, catalytic activity, domain/motif recognition, and descriptive text generation (Fang et al., 2024).

PFUA: Augmenting LLMs with Biological Tools

PFUA represents a departure from standard large language model (LLM) applications in biology by directly integrating LLMs with established computational biology tools. This coupling allows PFUA to move beyond text-based prediction and actively utilize resources designed for specific biological analyses. Instead of relying solely on the knowledge embedded within the LLM’s parameters, PFUA dynamically accesses and leverages external tools – such as those for sequence alignment or domain identification – as part of its reasoning process. This approach effectively extends the LLM’s capabilities by providing access to specialized functionalities and curated biological databases, enabling more accurate and informative predictions.

PFUA’s integration of large language models with computational biology tools allows it to execute tasks requiring specialized knowledge beyond the LLM’s pre-training data. Specifically, PFUA can perform sequence homology searches, identifying statistically significant similarities between protein or nucleic acid sequences, and Pfam domain analysis, which identifies conserved protein domains indicative of function and evolutionary relationships. These tools are not merely applied as post-processing steps; rather, their outputs are dynamically incorporated into the LLM’s reasoning process, enabling more accurate predictions and interpretations in biological contexts. This augmentation is critical for tasks where factual accuracy and domain-specific knowledge are paramount.

PFUA employs the ReAct framework, a process that alternates between generating reasoning traces and executing actions – in this case, accessing and utilizing external computational biology tools. This iterative approach allows the model to dynamically gather relevant information during prediction; rather than relying solely on pre-trained knowledge, PFUA can query tools to obtain specific data, such as sequence homology results or Pfam domain analyses, and incorporate these findings into subsequent reasoning steps. This interplay between reasoning and tool use enables PFUA to address complex biological questions that require up-to-date or specialized knowledge not readily available within the LLM’s parameters.

The PFUA framework demonstrably improves performance over existing baseline models, specifically BioMedGPT-R1, in molecular instruction following. Evaluation on the Mol-Instructions benchmark indicates an average improvement of 98.20% in ROUGE_L recall. This metric assesses the longest common subsequence between the generated text and reference text, providing a quantitative measure of prediction accuracy and the retention of key information. The substantial gain in ROUGE_L recall suggests PFUA’s tool-augmented reasoning capabilities lead to more precise and comprehensive responses compared to models relying solely on parametric knowledge.

Generative Rollout Policy Optimization (GRPO) successfully trains a policy to understand protein function.
Generative Rollout Policy Optimization (GRPO) successfully trains a policy to understand protein function.

Foundation and Refinement: Building a Robust Reasoning System

Qwen2.5-3B serves as the foundational language model within the Protein Foundation Understanding Architecture (PFUA) due to its inherent capabilities and performance gains achieved through initial cold-start supervised fine-tuning. This pre-training phase involves exposing the model to a dataset of protein-related text and data, allowing it to develop a base understanding of biological concepts and terminology before further specialized training. The resulting model demonstrates a strong capacity for subsequent refinement through reinforcement learning and tool integration, establishing a robust starting point for complex protein reasoning tasks and ultimately contributing to improved performance on benchmarks such as UniProtQA, PDB-QA, and CAFA.

Reinforcement Learning (RL) was implemented to optimize Qwen2.5-3B’s performance in protein reasoning tasks, utilizing the ROUGE_L metric as the primary reward signal. ROUGE_L assesses the longest common subsequence between the generated text and reference text, effectively encouraging the model to produce outputs that closely align with established biological knowledge and correct formatting. This RL-based fine-tuning process iteratively refines the model’s ability to not only generate logically sound reasoning paths, but also to present these conclusions in a structured and readily interpretable manner, as demonstrated by significant performance gains on the UniProtQA, PDB-QA, and CAFA benchmarks relative to the BioMedGPT-R1 baseline.

The PFUA framework integrates the Qwen2.5-3B language model with external tools, notably MMseqs2, to perform rapid sequence similarity searches. MMseqs2 enables efficient comparison of protein sequences against extensive databases such as the Swiss-Prot Database, allowing the model to identify homologous proteins and retrieve associated functional annotations. This capability is critical for augmenting Qwen2.5-3B’s reasoning process by providing access to experimentally validated protein information, thereby improving the accuracy and reliability of its predictions.

Integration of TMbed, a resource for analyzing transmembrane topology, significantly enhances the functional prediction capabilities of the PFUA framework. Benchmarking demonstrates substantial performance gains relative to BioMedGPT-R1, with a 233.53% improvement in ROUGE_L recall on the UniProtQA benchmark, a 24.97% improvement on the PDB-QA dataset, and a 55.57% improvement on the CAFA benchmark. These results indicate that incorporating TMbed-derived insights allows for more accurate and comprehensive protein function prediction within the LLM-based system.

Expanding the Horizon: Impact and Future Directions

The PFUA framework distinguishes itself through its inherent scalability and adaptability, extending far beyond the initial focus on protein function annotation. This approach isn’t limited to a single biological question; its modular design allows for application to diverse challenges, including gene regulatory network inference, metabolic pathway analysis, and even disease mechanism elucidation. By abstracting the problem-solving process into a sequence of prompting, function calling, understanding, and action, the framework can be readily retrained and repurposed with minimal architectural changes. This flexibility is particularly valuable in the rapidly evolving landscape of biological research, where new data and questions constantly emerge, demanding tools capable of swift adaptation and expansion – positioning PFUA as a versatile platform for tackling a wide spectrum of complex biological problems.

Large language models (LLMs) demonstrate impressive abilities, but their reasoning within specialized scientific fields remains limited by the data they were initially trained on. This research highlights a pathway to significantly augment LLM capabilities by seamlessly integrating external tools and curated knowledge sources. Rather than relying solely on pre-existing parameters, the framework enables LLMs to dynamically access and utilize specialized databases, computational resources, and expert knowledge during problem-solving. This externalization effectively transforms LLMs from repositories of static information into active agents capable of performing complex analyses, validating hypotheses, and generating novel insights across diverse scientific domains, extending beyond protein function to areas like genomics, drug discovery, and materials science. The ability to draw upon and synthesize information from these external resources not only improves accuracy but also empowers LLMs to tackle problems requiring up-to-date knowledge or specialized calculations, paving the way for more robust and reliable AI-driven scientific exploration.

Continued development hinges on refining how the PFUA framework selects the most pertinent external tools for a given biological question; current methods could benefit from algorithms that dynamically assess tool relevance and reliability. Equally crucial is the pursuit of more robust knowledge integration techniques, moving beyond simple concatenation of tool outputs to methods that resolve conflicting information and synthesize a coherent understanding. Future studies should explore methods like Bayesian networks or knowledge graphs to represent and reason with the combined insights, ultimately creating an AI system capable of not just accessing information, but truly understanding and applying it to solve complex scientific challenges.

The convergence of artificial intelligence and biological research promises a paradigm shift in the pace of scientific advancement and its impact on human wellbeing. This work represents a step towards realizing that future, envisioning AI not merely as a data analysis tool, but as an active partner in the scientific process. By automating and augmenting the reasoning capabilities of researchers, AI can accelerate the identification of promising research avenues, facilitate the interpretation of complex datasets, and ultimately expedite the development of novel therapies and preventative measures. The potential extends beyond specific disease treatments; a future powered by AI-driven discovery holds the promise of proactive healthcare, personalized medicine, and a deeper understanding of the fundamental mechanisms governing life itself, fostering a healthier and more resilient global population.

The pursuit of understanding complex biological systems, as demonstrated by PFUA, echoes a fundamental principle of elegant design: simplicity arising from interconnectedness. This research elegantly integrates large language models with computational tools, creating a system where each component’s function is defined by its relationship to the whole. Paul Erdős once said, “A mathematician knows a lot of things, but a good mathematician knows where to find them.” Similarly, PFUA doesn’t attempt to be every tool, but skillfully orchestrates their use, recognizing that true insight emerges not from isolated brilliance, but from the harmonious interplay of diverse knowledge sources. This approach emphasizes that a fragile system attempts to do too much; a robust one knows its limitations and leverages external strengths, mirroring the cold-start reasoning problem PFUA aims to solve.

Where Do We Go From Here?

The presented work, while a step toward bridging the gap between textual knowledge and computational biology, highlights a persistent truth: modularity, absent a deep understanding of the underlying system, is often an illusion of control. The agent’s reliance on specific tools, however effective in the short term, risks becoming brittle. If the system survives on duct tape – patching together functionalities without a cohesive architectural principle – it’s probably overengineered. The challenge isn’t simply adding tools, but cultivating an agent capable of dynamically assessing the relevance and limitations of any given instrument.

A crucial, and largely unresolved, problem remains the ‘cold start’ issue. This work addresses it, but a truly robust system must move beyond simply recalling pre-existing associations. It requires a capacity for analogical reasoning – the ability to map principles learned in one protein family to a novel, unseen sequence. Current approaches, focused on iterative refinement, treat proteins as black boxes; a deeper understanding necessitates modeling the process of protein function, not merely its outcome.

Ultimately, the pursuit of protein function understanding isn’t about building increasingly complex agents. It’s about uncovering the inherent simplicity of biological design. The most elegant solutions are rarely those with the most parts; rather, they are those that reveal the fundamental principles governing the whole. Future work should prioritize developing agents capable of not just using tools, but learning the underlying biophysical principles that dictate protein behavior.


Original article: https://arxiv.org/pdf/2601.03604.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2026-01-08 17:30