Crystal structure of the wheat dwarf virus Rep domain

The wheat dwarf virus Rep domain is an HUH‐endonuclease and is involved in rolling‐circle replication. HUH‐endonucleases, or HUH‐tags, form covalent protein‐ssDNA adducts by coordinating a divalent metal ion to cleave a specific ssDNA sequence and form a phosphotyrosine linkage. This protein‐ssDNA fusion is useful for various biotechnology applications such as cellular imaging, cellular barcoding, DNA‐guided protein localization, and single molecule manipulation of DNA‐tethered proteins. Solving the structure of the Rep domain in complex with DNA could present necessary information regarding HUH‐tag sequence specificity and allow for rational engineering of protein‐DNA interactions. Here, the structure of WDV Rep domain in the apo state was solved with a crystal diffracting to 1.24 Å. While ssDNA soaks were attempted, they proved ineffective. However, the solved structure represents a step towards solving protein‐ssDNA complex.