The human coronavirus HCoV-229E S-protein structure and receptor binding

Elife. 2019 Oct 25;8:e51230. doi: 10.7554/eLife.51230.

Abstract

The coronavirus S-protein mediates receptor binding and fusion of the viral and host cell membranes. In HCoV-229E, its receptor binding domain (RBD) shows extensive sequence variation but how S-protein function is maintained is not understood. Reported are the X-ray crystal structures of Class III-V RBDs in complex with human aminopeptidase N (hAPN), as well as the electron cryomicroscopy structure of the 229E S-protein. The structures show that common core interactions define the specificity for hAPN and that the peripheral RBD sequence variation is accommodated by loop plasticity. The results provide insight into immune evasion and the cross-species transmission of 229E and related coronaviruses. We also find that the 229E S-protein can expose a portion of its helical core to solvent. This is undoubtedly facilitated by hydrophilic subunit interfaces that we show are conserved among coronaviruses. These interfaces likely play a role in the S-protein conformational changes associated with membrane fusion.

Keywords: HCoV-229E; biochemistry; chemical biology; coronavirus; electron cryomicroscopy; spike protein; virus; x-ray crystallography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD13 Antigens / chemistry*
  • CD13 Antigens / metabolism*
  • Coronavirus 229E, Human / enzymology*
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • Humans
  • Protein Binding
  • Protein Domains
  • Spike Glycoprotein, Coronavirus / chemistry*
  • Spike Glycoprotein, Coronavirus / metabolism*

Substances

  • Spike Glycoprotein, Coronavirus
  • CD13 Antigens

Associated data

  • PDB/6U7E
  • PDB/6U7F
  • PDB/6U7G
  • PDB/6U7H

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.