{
  "id": 18355592,
  "title": "Prokaryotic homologs of the major vault protein form engineerable vault nanocapsules",
  "url": "https://urgent.news/2026/11/05/prokaryotic-homologs-of-the-major-vault-protein-form-engineerable",
  "topic": "science",
  "section": "Science",
  "published": "2026-11-05T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.11.04.764334v1?rss=1"
  },
  "original_language": "en",
  "account": "Vaults, the largest ribonucleoprotein particles found in eukaryotic cells, are composed of 78 major vault protein (MVP) copies, but their purpose has been a mystery for four decades since their discovery. MVP homologs have been identified in prokaryotes and bacteriophages, yet it was uncertain whether they form vaults. Researchers have now discovered that prokaryotic and bacteriophage MVP homologs can assemble into vault particles.\n\nBy examining around 15 billion proteins, the researchers identified MVP homologs in 29 bacterial and 4 archaeal phyla. They used size-exclusion chromatography to rapidly screen and isolate vault particles of eight homologs that were expressed in Escherichia coli. The cryo-electron microscopy structures of the phage homolog L05, obtained at high resolution, revealed a shell composed of 96 MVP chains enclosing a volume approximately 25% larger than human vaults, making it one of the largest protein shells of a defined size outside virus capsids.\n\nProkaryotic MVPs generally contain seven wall repeats, while eukaryotic MVPs consist of nine. The addition of wall repeats to L05 results in the formation of larger vaults. These prokaryotic vaults not only expand the known diversity of vault architecture but also provide a more accessible system for studying vault assembly and a size-tunable scaffold for cargo encapsulation.",
  "summary": "Vaults are the largest ribonucleoprotein particles in eukaryotic cells, built from 78 copies of the major vault protein (MVP), yet their function remains unknown four decades after their discovery. MVP homologs occur in prokaryotes and bacteriophages, but whether they form vaults is unknown. Here, we show that prokaryotic and bacteriophage MVP homologs assemble into vault particles. We surveyed…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}