Anthropic's research unveils the first 3D structure of vault particles in prokaryotes, advancing understanding of these enigmatic protein assemblies.
Anthropic has announced a significant breakthrough in biological research, revealing the first three-dimensional structure of a vault particle derived from prokaryotic cells. Vault particles, large hollow protein assemblies found across the tree of life, have been a mystery since their discovery in 1986 by Leonard Rome and Nancy Kedersha. Despite decades of study, their biological function remains unresolved. This new research, supported by Anthropic's AI model Claude, sheds light on the structure and potential applications of these enigmatic particles.
Using cryo-electron microscopy (cryo-EM), Anthropic's team uncovered the structure of a vault particle built from 96 copies of a single bacteriophage-derived protein, designated L05. The particle measures approximately 54 nanometers in length and 45 nanometers in width, enclosing about 25% more volume than its mammalian counterpart despite being shorter. Unlike mammalian vaults, which are composed of 78 protein copies with nine structural repeats per chain, the prokaryotic vault features seven repeats per chain and a flatter end-cap structure. The total mass of the prokaryotic vault is estimated at 9.5 megadaltons, making it one of the largest protein shells identified in prokaryotes.
The vault particles were produced in laboratory E. coli systems, providing researchers with a simpler and faster model for studying their assembly and evolution. Anthropic's screening process tested 44 proteins, with seven forming vault-like particles under electron microscopy. Cryo-EM confirmed vault shapes for four candidates, including two bacterial and two phage-derived proteins.
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