The structure of a prokaryotic viral envelope protein expands the landscape of membrane fusion proteins

Kamel El Omari, Sai Li, Abhay Kotecha, Thomas S. Walter, Eduardo A. Bignon, Karl Harlos, Pentti Somerharju, Felix De Haas, Daniel K. Clare, Mika Molin, Felipe Hurtado, Mengqiu Li, Jonathan M. Grimes, Dennis H. Bamford, Nicole D. Tischler (Corresponding author), Juha T. Huiskonen (Corresponding author), David I. Stuart (Corresponding author), Elina Roine (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

27 Citations (Scopus)
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Lipid membrane fusion is an essential function in many biological processes. Detailed mechanisms of membrane fusion and the protein structures involved have been mainly studied in eukaryotic systems, whereas very little is known about membrane fusion in prokaryotes. Haloarchaeal pleomorphic viruses (HRPVs) have a membrane envelope decorated with spikes that are presumed to be responsible for host attachment and membrane fusion. Here we determine atomic structures of the ectodomains of the 57-kDa spike protein VP5 from two related HRPVs revealing a previously unreported V-shaped fold. By Volta phase plate cryo-electron tomography we show that VP5 is monomeric on the viral surface, and we establish the orientation of the molecules with respect to the viral membrane. We also show that the viral membrane fuses with the host cytoplasmic membrane in a process mediated by VP5. This sheds light on protein structures involved in prokaryotic membrane fusion.

Original languageEnglish
Article number846
Number of pages11
JournalNature Communications
Issue number1
Publication statusPublished - 1 Dec 2019


  • Archaeal Viruses/chemistry
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • Electron Microscope Tomography
  • Halorubrum/virology
  • Membrane Fusion
  • Membrane Fusion Proteins/chemistry
  • Protein Domains
  • Protein Folding
  • Viral Envelope Proteins/chemistry
  • Virion/chemistry


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