Recognition of eIF4G by rotavirus NSP3 reveals a basis for mRNA circularization.
Rotaviruses, segmented double-stranded RNA viruses, co-opt the eukaryotic translation machinery with the aid of nonstructural protein 3 (NSP3), a rotaviral functional homolog of the cellular poly(A) binding protein (PABP). NSP3 binds to viral mRNA 3' consensus sequences and circularizes mRNA via interactions with eIF4G. Here, we present the X-ray structure of the C-terminal domain of NSP3 (NSP3-C) recognizing a fragment of eIF4GI. Homodimerization of NSP3-C yields a symmetric, elongated, largely alpha-helical structure with two hydrophobic eIF4G binding pockets at the dimer interface. Site-directed mutagenesis and isothermal titration calorimetry documented that NSP3 and PABP use analogous eIF4G recognition strategies, despite marked differences in tertiary structure.
Groft
Caroline M
CM
Laboratory of Molecular Biophysics, New York, NY 10021, USA.
Burley
Stephen K
SK
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D039603:Eukaryotic Initiation Factor-4G; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000737:chemistry* / Q000378:metabolism; D020836:Protein Structure, Quaternary; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000378:metabolism
D002352:Carrier Proteins; D039603:Eukaryotic Initiation Factor-4G; C082740:NSP3 protein, Rotavirus; D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D017361:Viral Nonstructural Proteins