The severe acute respiratory syndrome-coronavirus replicative protein nsp9 is a single-stranded RNA-binding subunit unique in the RNA virus world.
The recently identified etiological agent of the severe acute respiratory syndrome (SARS) belongs to Coronaviridae (CoV), a family of viruses replicating by a poorly understood mechanism. Here, we report the crystal structure at 2.7-A resolution of nsp9, a hitherto uncharacterized subunit of the SARS-CoV replicative polyproteins. We show that SARS-CoV nsp9 is a single-stranded RNA-binding protein displaying a previously unreported, oligosaccharide/oligonucleotide fold-like fold. The presence of this type of protein has not been detected in the replicative complexes of RNA viruses, and its presence may reflect the unique and complex CoV viral replication/transcription machinery.
Architecture et Fonction des Macromolécules Biologiques, Unité Mixte de Recherche 6098 Centre National de la Recherche Scientifique and Universités Aix-Marseille I et II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
Marie-Pierre
MP
Egloff
François
F
Ferron
Valérie
V
Campanacci
Sonia
S
Longhi
Corinne
C
Rancurel
Hélène
H
Dutartre
Eric J
EJ
Snijder
Alexander E
AE
Gorbalenya
Christian
C
Cambillau
Bruno
B
Canard
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004277:DNA, Single-Stranded / Q000378:metabolism*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics* / Q000378:metabolism; D020539:Sequence Analysis, Protein; D045169:Severe Acute Respiratory Syndrome / Q000378:metabolism* / Q000821:virology; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
D004277:DNA, Single-Stranded; D016601:RNA-Binding Proteins; D014764:Viral Proteins; C483945:nsp9 protein, SARS virus; D012313:RNA