Potato yellow mosaic geminivirus AC2 protein is a sequence non-specific DNA binding protein

The AC2 protein of potato yellow mosaic geminivirus (PYMV) is by analogy with related geminiviruses thought to be a transcriptional activator protein. We have over-expressed the AC2 open reading frame in E. coli and purified the protein from bacterial extracts to near homogeneity. We have studied the interaction of the AC2 protein with DNA and from gel retardation assays shown that it binds both double-stranded (ds) and single-stranded (ss) DNA non-specifically. The binding to PYMV intergenic region ds DNA appeared to be independent of the presence of zinc ions and did not require the protein to be phosphorylated.