This domain is found in at the C terminus of group 3 Schlafen proteins from mammals, and represents the DNA/RNA helicase domain [2]. Schlafen proteins are involved in the control of cell proliferation, induction of immune responses, and in the regulation of viral replication [1,2,3]. These proteins inhibit DNA replication and promote cell death in response to DNA damage. They play a role in genome surveillance to kill cells with defective replication [3]. This domain is also found in various uncharacterised prokaryotic proteins fused to a DNA helicase, GIY-YIG or PD-(D/E)XK catalytic domain or HsdR-N(terminal) domain, which are similar to AAA DNA helicase, Type III restriction enzyme ATPase, RecD and RuvB helicase [3].

1: The schlafen family of proteins and their regulation by interferons. Mavrommatis E, Fish EN, Platanias LC; J Interferon Cytokine Res. 2013;33:206-210. PMID:23570387

2: Subcellular localization of the Schlafen protein family. Neumann B, Zhao L, Murphy K, Gonda TJ; Biochem Biophys Res Commun. 2008;370:62-66. PMID:18355440

3: A protein architecture guided screen for modification dependent restriction endonucleases. Lutz T, Flodman K, Copelas A, Czapinska H, Mabuchi M, Fomenkov A, He X, Bochtler M, Xu SY; Nucleic Acids Res. 2019;47:9761-9776. PMID:31504772