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 Bignon, Karl Harlos, Pentti Somerharju, Felix de Haas, Daniel Clare, Mika Molin, Felipe Hurtado, Mengqiu Li, Jonathan M. Grimes, Dennis Henry Bamford, Nicole D. Tischler, Juha T. Huiskonen, David I. Stuart, Elina Roine

Research output: Contribution to journalArticleScientificpeer-review


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
JournalNature Communications
Number of pages11
Publication statusPublished - 19 Feb 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1183 Plant biology, microbiology, virology
  • Archaea
  • Virus
  • Prokaryote
  • 1182 Biochemistry, cell and molecular biology
  • Cryo-ET
  • X-ray crystal structure
  • Membrane fusion
  • Fusion proteins

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