Claude Helps Map a Protein Shell Science Left Unexplained for 40 Years
Anthropic's biology lab, working with its Claude model, has produced the first 3D structure of a vault particle from a prokaryotic cell — a protein shell whose function has baffled scientists since 1986.
Vaults are large, hollow protein barrels found in nearly all human cells, but researchers have never established what they do. They are missing from the lab organisms biologists rely on most, and mice bred without them develop normally, leaving no obvious defect to study. Anthropic's team set out to find whether distant relatives of the vault protein found in bacteria and the viruses that infect them actually assemble into vault-like particles — and found that they do.
The team screened 44 candidate proteins, produced 15 in living E. coli, and confirmed seven had assembled into vault-like particles under an electron microscope. They then mapped one in detail: a phage-derived vault built from 96 copies of a single protein, roughly 54 nanometers long and 45 wide, enclosing about 25% more volume than the mammalian version despite being shorter. Claude searched a database of about 15 billion predicted proteins, designed DNA constructs, optimized the isolation method, and ran the cryo-electron microscopy processing pipeline. A purification that conventionally takes three days took about 90 minutes; a first structural model was ready 34 hours later, work the team estimates would normally have taken weeks.
The most striking detail is what the structure revealed: a pocket in each of the 96 protein copies holds a small molecule the team cannot yet identify, but which Claude noted resembles coenzyme A, a common cellular helper molecule. If confirmed, that would be an early hint at vault function. The team also engineered a larger vault by duplicating part of the wall protein, increasing enclosed volume by about 20%, and showed that single changes near the cap can prevent the shell from closing.
The work is a demonstration of AI-assisted science rather than a biological breakthrough: the function of vaults remains unknown, and the particles have so far been made only in E. coli, not in their natural hosts. The team also documented Claude's failures — a flawed protocol that set the project back two weeks, and a cryo-EM processing error that produced a mirror-image map. But the overall pace, under four months from start to structure, is the point. Anthropic is releasing the findings early to show how its model can be embedded across a research workflow, not just used for isolated tasks.