A 193-amino acid fragment of the SARS coronavirus S protein efficiently binds angiotensin-converting enzyme 2

J Biol Chem. 2004 Jan 30;279(5):3197-201. doi: 10.1074/jbc.C300520200. Epub 2003 Dec 11.

Abstract

The coronavirus spike (S) protein mediates infection of receptor-expressing host cells and is a critical target for antiviral neutralizing antibodies. Angiotensin-converting enzyme 2 (ACE2) is a functional receptor for the coronavirus (severe acute respiratory syndrome (SARS)-CoV) that causes SARS. Here we demonstrate that a 193-amino acid fragment of the S protein (residues 318-510) bound ACE2 more efficiently than did the full S1 domain (residues 12-672). Smaller S protein fragments, expressing residues 327-510 or 318-490, did not detectably bind ACE2. A point mutation at aspartic acid 454 abolished association of the full S1 domain and of the 193-residue fragment with ACE2. The 193-residue fragment blocked S protein-mediated infection with an IC(50) of less than 10 nm, whereas the IC(50) of the S1 domain was approximately 50 nm. These data identify an independently folded receptor-binding domain of the SARS-CoV S protein.

MeSH terms

  • Alanine / chemistry
  • Angiotensin-Converting Enzyme 2
  • Carboxypeptidases / chemistry*
  • Carboxypeptidases / metabolism
  • Cell Line
  • Cysteine / chemistry
  • Dose-Response Relationship, Drug
  • Electrophoresis, Polyacrylamide Gel
  • Flow Cytometry
  • Glutamic Acid / chemistry
  • Humans
  • Inhibitory Concentration 50
  • Membrane Glycoproteins / chemistry*
  • Mutation
  • Peptidyl-Dipeptidase A
  • Point Mutation
  • Protein Binding
  • Protein Structure, Tertiary
  • Severe acute respiratory syndrome-related coronavirus / metabolism*
  • Spike Glycoprotein, Coronavirus
  • Transfection
  • Viral Envelope Proteins / chemistry*

Substances

  • Membrane Glycoproteins
  • Spike Glycoprotein, Coronavirus
  • Viral Envelope Proteins
  • spike glycoprotein, SARS-CoV
  • spike protein, mouse hepatitis virus
  • Glutamic Acid
  • Carboxypeptidases
  • Peptidyl-Dipeptidase A
  • ACE2 protein, human
  • Angiotensin-Converting Enzyme 2
  • Cysteine
  • Alanine