RFD4-Proteina: How an AI Designed Enzymes to Make Lenacapavir, and Why Only 4 of 67 Worked

By Carlos Montiel | Enterprise AI Specialist
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Published: 2026-10-28 | By: Carlos Montiel | Reading time: ~5 minutes
RFD4-Proteina: how an AI designed enzymes to make lenacapavir and why only 4 of 67 worked

An open protein-design model produced 67 candidate enzymes for one step in the synthesis of an HIV drug; four showed activity and the best converted 79% of the substrate.

What Was Done

According to a University of Manchester release (October 22, 2026) and Phys.org coverage, the University of Washington's Institute for Protein Design (IPD), led by David Baker, and Nvidia developed RFD4-Proteina, a unified generative model that combines the IPD's RosettaFold Diffusion line with Nvidia's Proteina-Complexa. Researchers at the Manchester Institute of Biotechnology (Anthony Green, Henry Jones and Zefei Xu) tested it on a concrete challenge: designing enzymes that catalyze an amide bond formation step in the synthesis of lenacapavir, an HIV prevention drug.

The Lab Numbers

Designs tested in the lab 67 Designs with clear activity 4 Best enzyme: amine conversion 79% Selectivity favors the required S enantiomer Design success (vs. earlier models) 5 to 10 times higher (computational benchmarks) Generation speed 5 to 10 times faster

The 4-of-67 rate is what makes the result honest: AI design doesn't deliver a finished enzyme, it delivers a few candidates to validate. Even so, the best enzyme also suppressed a competing reaction with water, a typical problem in this kind of catalysis. Green called the initial results "spectacular"; Baker said the model "will open the door to new solutions in medicine, sustainability, materials and biotechnology."

How to Read the Result

The 5-to-10x comparisons come from the authors' own computational tests, not an independent evaluation. The work is a preprint ("Biomolecular design through latent reasoning with RFD4-Proteina") and hasn't yet been peer reviewed. The model is open source under a BSD-3 license, so third parties can reproduce it.

What the report doesn't say: there's no data on industrial scale-up, cost per kilogram, or comparison with the current chemical or enzymatic routes to lenacapavir. It's a proof of concept on a single reaction.

What It Means for a Company

What it means for your company: if you work in pharma, agribusiness or chemicals, the practical shift is that biocatalyst design moves from months of trial and error to hundreds of candidates generated and filtered computationally, with experimental validation at the end. The competitive edge will lie with the lab that validates fast, not with the model, which is open. And for any sector: ask scientific-AI vendors for their real lab success rate, not just the benchmark. Inquiries: info@guatemalia.com.

Sources: University of Manchester (October 22, 2026), Phys.org (October 23, 2026). Preprint data not yet peer reviewed.

Carlos Montiel
Enterprise AI Solutions Architect
Specialist in LLMs, Agents, and Orchestration
guatemalia.com/#contacto · info@guatemalia.com

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Contact Carlos Montiel

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