Central ions and lateral asparagine/glutamine zippers stabilize the post-fusion hairpin conformation of the SARS coronavirus spike glycoprotein.
The coronavirus spike glycoprotein is a class I membrane fusion protein with two characteristic heptad repeat regions (HR1 and HR2) in its ectodomain. Here, we report the X-ray structure of a previously characterized HR1/HR2 complex of the severe acute respiratory syndrome coronavirus spike protein. As expected, the HR1 and HR2 segments are organized in antiparallel orientations within a rod-like molecule. The HR1 helices form an exceptionally long (120 A) internal coiled coil stabilized by hydrophobic and polar interactions. A striking arrangement of conserved asparagine and glutamine residues of HR1 propagates from two central chloride ions, providing hydrogen-bonding "zippers" that strongly constrain the path of the HR2 main chain, forcing it to adopt an extended conformation at either end of a short HR2 alpha-helix.
Duquerroy
Stéphane
S
Laboratoire de Virologie Moléculaire and Structurale, UMR 2472/1157 CNRS-INRA and IFR 115, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.
Vigouroux
Armelle
A
Rottier
Peter J M
PJ
Rey
Félix A
FA
Bosch
Berend Jan
BJ
D000595:Amino Acid Sequence; D001216:Asparagine / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism*; D007477:Ions / Q000737:chemistry / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D045473:Severe acute respiratory syndrome-related coronavirus / Q000737:chemistry* / Q000378:metabolism*; D012492:Salts / Q000737:chemistry / Q000378:metabolism; D064370:Spike Glycoprotein, Coronavirus; D055672:Static Electricity; D013816:Thermodynamics; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000378:metabolism*
D007477:Ions; D008562:Membrane Glycoproteins; D012492:Salts; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; D005973:Glutamine; D001216:Asparagine