Unlocking Multimodal Protein Language Models at Inference Time

Yi Zhou, Wang Qipeng, Yunqing Liu, Jun Xia, Li Qing, Wenqi Fan


Abstract
Multimodal protein language models (pLMs) learn joint protein sequence-structure distributions, and their generation performance should also depend critically on inference-time sampling strategies. Yet prior work has focused more on model training than on how inference-time strategies behave. In this paper, we establish a three-stage investigation framework to empirically study the inference design space of multimodal pLMs across three representative pLMs and four fundamental tasks. We evaluate vanilla sampling, task-specific classifier-free guidance, and reward-guided beam search on multimodal pLMs, corresponding to controls over sampling distributions, per-step logits, and parallel trajectories. Throughout the complementary advancements centered on exploration-exploitation trade-off, we (1) reveal the suboptimality of default inference protocols and identify task-oriented sampling preferences; (2) observe substantial quantitative gains across tasks, consistently boosting the upper bound performance of multimodal pLMs without updating model parameters; (3) derive conclusions about base models that differ from prior consensus. Our code is available at: https://github.com/EchoChou990919/mplm_inference.
Anthology ID:
2026.emnlp-main.1539
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
35132–35151
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1539/
DOI:
Bibkey:
Cite (ACL):
Yi Zhou, Wang Qipeng, Yunqing Liu, Jun Xia, Li Qing, and Wenqi Fan. 2026. Unlocking Multimodal Protein Language Models at Inference Time. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 35132–35151, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Unlocking Multimodal Protein Language Models at Inference Time (Zhou et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1539.pdf