Oligomeric states of bacteriophage T7 gene 4 primase/helicase.

  title={Oligomeric states of bacteriophage T7 gene 4 primase/helicase.},
  author={Donald J. Crampton and Melanie D. Ohi and Udi Qimron and Thomas Walz and Charles C. Richardson},
  journal={Journal of molecular biology},
  volume={360 3},
Electron microscopic and crystallographic data have shown that the gene 4 primase/helicase encoded by bacteriophage T7 can form both hexamers and heptamers. After cross-linking with glutaraldehyde to stabilize the oligomeric protein, hexamers and heptamers can be distinguished either by negative stain electron microscopy or electrophoretic analysis using polyacrylamide gels. We find that hexamers predominate in the presence of either dTTP or beta,gamma-methylene dTTP whereas the ratio between… CONTINUE READING