Download MendeleyVariable Internal Flexibility Characterizes the Helical Capsid Formed by Agrobacterium Vire2 Protein on Single-Stranded DNA.
Bharat, T.A.M., Zbaida, D., Eisenstein, M., Frankenstein, Z., Mehlman, T., Weiner, L., Sorzano, C.O.S., Barak, Y., Albeck, S., Briggs, J.A.G., Wolf, S.G., Elbaum, M.(2013) Structure 21: 1158
- PubMed: 23769668
- DOI: https://doi.org/10.1016/j.str.2013.04.027
- Primary Citation of Related Structures:
4BLF - PubMed Abstract:
Agrobacterium is known for gene transfer to plants. In addition to a linear ssDNA oligonucleotide, Agrobacterium tumefaciens secretes an abundant ssDNA-binding effector, VirE2. In many ways VirE2 adapts the conjugation mechanism to transform the eukaryotic host. The crystal structure of VirE2 shows two compact domains joined by a flexible linker. Bound to ssDNA, VirE2 forms an ordered solenoidal shell, or capsid known as the T-complex. Here, we present a three-dimensional reconstruction of the VirE2-ssDNA complex using cryo-electron microscopy and iterative helical real-space reconstruction. High-resolution refinement was not possible due to inherent heterogeneity in the protein structure. By a combination of computational modeling, chemical modifications, mass spectroscopy, and electron paramagnetic resonance, we found that the N-terminal domain is tightly constrained by both tangential and longitudinal links, while the C terminus is weakly constrained. The quaternary structure is thus rigidly assembled while remaining locally flexible. This flexibility may be important in accommodating substrates without sequence specificity.
Organizational Affiliation:
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel.
