Characterization of DNA-binding activity of Z alpha domains from poxviruses and the importance of the beta-wing regions in converting B-DNA to Z-DNA.
The E3L gene is essential for pathogenesis in vaccinia virus. The E3L gene product consists of an N-terminal Z alpha domain and a C-terminal double-stranded RNA (dsRNA) binding domain; the left-handed Z-DNA-binding activity of the Z alpha domain of E3L is required for viral pathogenicity in mice. E3L is highly conserved among poxviruses, including the smallpox virus, and it is likely that the orthologous Z alpha domains play similar roles. To better understand the biological function of E3L proteins, we have investigated the Z-DNA-binding behavior of five representative Z alpha domains from poxviruses. Using surface plasmon resonance (SPR), we have demonstrated that these viral Z alpha domains bind Z-DNA tightly. Ability of Z alpha(E3L) converting B-DNA to Z-DNA was measured by circular dichroism (CD). The extents to which these Z alphas can stabilize Z-DNA vary considerably. Mutational studies demonstrate that residues in the loop of the beta-wing play an important role in this stabilization. Notably the Z alpha domain of vaccinia E3L acquires ability to convert B-DNA to Z-DNA by mutating amino acid residues in this region. Differences in the host cells of the various poxviruses may require different abilities to stabilize Z-DNA; this may be reflected in the observed differences in behavior in these Zalpha proteins.
Quyen
Dong Van
DV
Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea.
Ha
Sung Chul
SC
Lowenhaupt
Ky
K
Rich
Alexander
A
Kim
Kyeong Kyu
KK
Kim
Yang-Gyun
YG
D000595:Amino Acid Sequence; D018147:Chordopoxvirinae; D004247:DNA / Q000737:chemistry; D043542:DNA, Z-Form / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D008239:Lysine / Q000737:chemistry; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D020349:Surface Plasmon Resonance; D013912:Threonine / Q000737:chemistry; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D043542:DNA, Z-Form; D004268:DNA-Binding Proteins; C081374:E3L protein, Vaccinia virus; D016601:RNA-Binding Proteins; D014764:Viral Proteins; D013912:Threonine; D004247:DNA; D008239:Lysine