Cooperative interaction of Agrobacterium VirE2 protein with single-stranded DNA: implications for the T-DNA transfer process.
AUTOR(ES)
Citovsky, V
RESUMO
Induction of Agrobacterium tumefaciens vir gene expression by wounded plant cells results in production of a free transferable single-stranded (ss) copy of T-DNA, the T-strand. One of the Vir proteins, the VirE2 polypeptide, is a ssDNA-binding protein. In the present work, interaction of nopaline-specific VirE2 protein (Mr 69,000) with ssDNA was studied by using nitrocellulose filter binding, gel retardation, and electron microscopy techniques. The VirE2 protein was found to bind to ssDNA molecules with strong cooperativity, forming VirE2-ssDNA complexes with a binding site of 28-30 nucleotides. The VirE2-ssDNA complexes are stable at high salt concentrations and resistant to exonucleolytic activity. When examined under the electron microscope, the VirE2 protein converted collapsed free ssDNA molecules into unfolded and extended structures. The structure and properties of VirE2-ssDNA complexes predict possible functions in Agrobacterium virulence to (i) protect the T-strands from cellular nucleases and (ii) facilitate transfer of the T-strands through bacterial membranes possibly by specific interaction with putative membrane pores formed in plant-induced Agrobacterium cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=286652Documentos Relacionados
- Cooperative binding of Agrobacterium tumefaciens VirE2 protein to single-stranded DNA.
- The Agrobacterium tumefaciens Chaperone-Like Protein, VirE1, Interacts with VirE2 at Domains Required for Single-Stranded DNA Binding and Cooperative Interaction†
- Agrobacterium rhizogenes GALLS Protein Substitutes for Agrobacterium tumefaciens Single-Stranded DNA-Binding Protein VirE2
- Agrobacterium VirE2 protein mediates nuclear uptake of single-stranded DNA in plant cells.
- VirE1 protein mediates export of the single-stranded DNA-binding protein VirE2 from Agrobacterium tumefaciens into plant cells.