Biochemical characterization of the equine arteritis virus helicase suggests a close functional relationship between arterivirus and coronavirus helicases.
The arterivirus equine arteritis virus nonstructural protein 10 (nsp10) has previously been predicted to contain a Zn finger structure linked to a superfamily 1 (SF1) helicase domain. A recombinant form of nsp10, MBP-nsp10, was produced in Escherichia coli as a fusion protein with the maltose-binding protein. The protein was partially purified by affinity chromatography and shown to have ATPase activity that was strongly stimulated by poly(dT), poly(U), and poly(dA) but not by poly(G). The protein also had both RNA and DNA duplex-unwinding activities that required the presence of 5' single-stranded regions on the partial-duplex substrates, indicating a 5'-to-3' polarity in the unwinding reaction. Results of this study suggest a close functional relationship between the arterivirus nsp10 and the coronavirus helicase, for which NTPase and duplex-unwinding activities were recently demonstrated. In a number of biochemical properties, both arterivirus and coronavirus SF1 helicases differ significantly from the previously characterized RNA virus SF1 and SF2 enzymes. Thus, the combined data strongly support the idea that nidovirus helicases may represent a separate group of RNA virus-encoded helicases with distinct properties.
Seybert
A
A
Institute of Virology and Immunology, University of Würzburg, Würzburg, Germany.
van Dinten
L C
LC
Snijder
E J
EJ
Ziebuhr
J
J
D018528:ATP-Binding Cassette Transporters; D000251:Adenosine Triphosphatases / Q000378:metabolism; D018018:Arterivirus / Q000201:enzymology*; D002352:Carrier Proteins / Q000378:metabolism; D017934:Coronavirus / Q000201:enzymology*; D004265:DNA Helicases / Q000502:physiology*; D004279:DNA, Viral / Q000378:metabolism; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases / Q000378:metabolism; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D020365:RNA Helicases / Q000502:physiology*; D012367:RNA, Viral / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D017361:Viral Nonstructural Proteins / Q000502:physiology*; D016335:Zinc Fingers
D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D004279:DNA, Viral; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D017361:Viral Nonstructural Proteins; C461599:maltose transport system, E coli; D012965:Sodium Chloride; D000251:Adenosine Triphosphatases; D020558:GTP Phosphohydrolases; D004265:DNA Helicases; D020365:RNA Helicases