RNA binding activity of NIa proteinase of tobacco etch potyvirus.
The C-terminal domain of NIa protein (NIaPro) from tobacco etch potyvirus (TEV) is a sequence-specific proteinase required for processing of the viral polyprotein. This proteinase also interacts with NIb, the TEV RNA-dependent RNA polymerase. NIaPro and two NIaPro-containing polyproteins (NIa and 6/NIa) were analyzed from extracts of recombinant Escherichia coli. Using RNA-protein blot and UV-crosslinking assays, NIaPro and the NIaPro-containing polyproteins were shown to possess RNA-binding activity. NIaPro bound nonspecifically to several RNAs, including plus- and minus-strands of the TEV 5' and 3' noncoding regions. Saturation binding data obtained using the UV-crosslinking assay were consistent with a possible cooperative RNA-binding activity of NIaPro. In addition, the RNA-binding activities of NIaPro and full-length NIa protein were similar. Based on its RNA-binding activity and other known functions, NIaPro or a NIaPro-containing polyprotein is proposed to serve one or more direct roles during TEV RNA synthesis.
Daròs
J A
JA
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, USA.
Carrington
J C
JC
D010450:Endopeptidases; D010947:Plants, Toxic; D017800:Potyvirus / Q000201:enzymology*; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000378:metabolism*; D014026:Nicotiana / Q000821:virology*; D014764:Viral Proteins / Q000378:metabolism*
D016601:RNA-Binding Proteins; D014764:Viral Proteins; D010450:Endopeptidases; C059992:nuclear inclusion protein a, mosaic viruses