Structure of arterivirus nsp4. The smallest chymotrypsin-like proteinase with an alpha/beta C-terminal extension and alternate conformations of the oxyanion hole.
Arteriviruses are enveloped, positive-stranded RNA viruses and include pathogens of major economic concern to the swine- and horse-breeding industries. The arterivirus replicase gene encodes two large precursor polyproteins that are processed by the viral main proteinase nonstructural protein 4 (nsp4). The three-dimensional structure of the 21-kDa nsp4 from the arterivirus prototype equine arteritis virus has been determined to 2.0 A resolution. Nsp4 adopts the smallest known chymotrypsin-like fold with a canonical catalytic triad of Ser-120, His-39, and Asp-65, as well as a novel alpha/beta C-terminal extension domain that may play a role in mediating protein-protein interactions. In different copies of nsp4 in the asymmetric unit, the oxyanion hole adopts either a collapsed inactive conformation or the standard active conformation, which may be a novel way of regulating proteolytic activity.
Barrette-Ng
Isabelle H
IH
Canadian Institutes for Health Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Ng
Kenneth K-S
KK
Mark
Brian L
BL
Van Aken
Danny
D
Cherney
Maia M
MM
Garen
Craig
C
Kolodenko
Yuliya
Y
Gorbalenya
Alexander E
AE
Snijder
Eric J
EJ
James
Michael N G
MN
D000595:Amino Acid Sequence; D000838:Anions; D018018:Arterivirus / Q000201:enzymology*; D001224:Aspartic Acid / Q000737:chemistry; D001665:Binding Sites; D020134:Catalytic Domain; D002918:Chymotrypsin / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006639:Histidine / Q000737:chemistry; D008957:Models, Genetic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000737:chemistry; D012697:Serine Endopeptidases / Q000737:chemistry*
D000838:Anions; D001224:Aspartic Acid; D012694:Serine; D006639:Histidine; D012697:Serine Endopeptidases; D002918:Chymotrypsin