No abstract

be necessary for this task, so helicase assays were conducted to assess the activity of each of the Rep proteins. We found that Rep40 has a higher helicase activity compared to Rep68 implying its role as the molecular motor as logical. Since Rep68 doesn't unwind DNA nearly as well as Rep40, we hypothesized another role that is linked to its oligomeric capacity. Using AUC, we have discovered Rep68's ability to not only form higher order molecular complexes on its own, but depending on the DNA substrate, the molecular weight of the DNA/protein complex can change. In the presence of the inverted-terminal repeats (ITR), it forms a structure that is smaller and distinct from the structure formed with ssDNA and Rep68. Currently, we have cryo-EM data on the ssDNA/Rep68 complex and we have negative stain data on the ITR/Rep68 complex. All together, Rep68's flexibility appears to imply a more structural role for Rep68 to help hold the DNA in place as Rep40 pushes the DNA into the capsid.

conditions (e.g. stress). TA toxins have a bacteriostatic effect that can lead to cell death if sustained. Although the mechanisms of action for a few TA toxins have been uncovered, the intracellular targets of many others have not been identified. Our latest structural and functional data on such complexes will be presented.

No abstract