This is an N-terminal domain on putative NWD NACHT proteins, signal transducing ATPases which undergo ligand-induced oligomerisation.

1: Diversity and Variability of NOD-Like Receptors in Fungi. Dyrka W, Lamacchia M, Durrens P, Kobe B, Daskalov A, Paoletti M, Sherman DJ, Saupe SJ; Genome Biol Evol. 2014;6:3137-3158. PMID:25398782