The crystal structure of the human smacovirus 1 Rep domain

Replication initiator proteins (Reps) from the HUH endonuclease family process specific single‐stranded DNA sequences to initiate rolling‐circle replication in viruses. Here, the first crystal structure of the apo state of a Rep domain from the smacovirus family is reported. The structure of the human smacovirus 1 Rep domain was obtained at 1.33 Å resolution and represents an expansion of the HUH endonuclease superfamily, allowing greater diversity in bioconjugation‐tag applications. The structure of the human smacovirus 1 Rep domain was obtained at 1.33 Å resolution. This new HUH endonuclease offers a new ssDNA‐binding sequence specificity that will be exploited to increase orthogonality among Rep families.