Multiple Enzymatic Activities Associated with Severe Acute Respiratory Syndrome Coronavirus Helicase

• DOI: 10.1128/jvi.78.11.5619-5632.2004
• Publication Date: 2004-05-12T20:28:03Z
• Authors: Konstantin A. Ivanov; Volker Thiel; Jessika C. Dobbe; Yvonne van der Meer; Eric J. Snijder; John Ziebuhr
• Keywords: RNA Helicase A; Coronavirus; Processivity

Severe acute respiratory syndrome coronavirus (SARS-CoV), a newly identified group 2 coronavirus, is the causative agent of severe syndrome, life-threatening form pneumonia in humans. Coronavirus replication and transcription are highly specialized processes cytoplasmic RNA synthesis that localize to virus-induced membrane structures were recently proposed involve complex enzymatic machinery that, besides RNA-dependent polymerase, helicase, protease activities, also involves series RNA-processing enzymes not found most other virus families. Here, we characterized activities recombinant SARS-CoV helicase (nonstructural protein [nsp] 13), superfamily 1 with an N-terminal zinc-binding domain. We report nsp13 has both DNA duplex-unwinding activities. unwinds its substrates 5'-to-3' direction features remarkable processivity, allowing efficient strand separation extended regions double-stranded DNA. Characterization nsp13-associated (deoxy)nucleoside triphosphatase ([dNTPase) revealed all natural nucleotides deoxynucleotides nsp13, ATP, dATP, GTP being hydrolyzed slightly more efficiently than nucleotides. Furthermore, established 5'-triphosphatase activity for which may be involved formation 5' cap structure viral RNAs. The data suggest (d)NTPase have common active site. Finally, SARS-CoV-infected Vero E6 cells, localizes membranes appear derived from endoplasmic reticulum likely site synthesis.