title: The nonstructural protein 2C of a Picorna-like virus displays nucleic acid helix destabilizing activity that can be functionally separated from its ATPase activity.
abstract: Picorna-like viruses in the Picornavirales order are a large group of positive-strand RNA viruses that include numerous important pathogens for plants, insects, and humans. In these viruses, nonstructural protein 2C is one of the most conserved proteins and contains ATPase activity and putative RNA helicase activity. Here we expressed 2C protein of Ectropis obliqua picorna-like virus (EoV; genus Iflavirus, family Iflaviridae, order Picornavirales) in a eukaryotic expression system and determined that EoV 2C displays ATP-independent nucleic acid helix destabilizing and strand annealing acceleration activity in a concentration-dependent manner, indicating that this picornaviral 2C is more like an RNA chaperone than like the previously predicted RNA helicase. Our further characterization of EoV 2C revealed that divalent metal ions, such as Mg(2+) and Zn(2+), inhibit 2C-mediated helix destabilization to different extents. Moreover, we determined that EoV 2C also contains ATPase activity like that of other picornaviral 2C proteins and further assessed the functional relevance between its RNA chaperone-like and ATPase activities using mutational analysis as well as their responses to Mg(2+). Our data show that, when one of the two 2C activities was dramatically inhibited or almost abolished, the other activity could remain intact, showing that the RNA chaperone-like and ATPase activities of EoV 2C can be functionally separated. This report reveals that a picorna-like virus 2C protein displays RNA helix destabilizing and strand annealing acceleration activity, which may be critical for picornaviral replication and pathogenesis, and should foster our understanding of picorna-like viruses and viral RNA chaperones.
authors: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors: Zhenyun
authors: Z
authors: Cheng
authors: Jie
authors: J
authors: Yang
authors: Hongjie
authors: H
authors: Xia
authors: Yang
authors: Y
authors: Qiu
authors: Zhaowei
authors: Z
authors: Wang
authors: Yajuan
authors: Y
authors: Han
authors: Xiaoling
authors: X
authors: Xia
authors: Cheng-Feng
authors: CF
authors: Qin
authors: Yuanyang
authors: Y
authors: Hu
authors: Xi
authors: X
authors: Zhou
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D012328:RNA Viruses / Q000201:enzymology* / Q000235:genetics; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D000251:Adenosine Triphosphatases; D020365:RNA Helicases