Ski2 from yeast is an helicase with an overall similar structure to MTR4 proteins. It has an arch domain with an helical stalk/elbow (Pfam:PF21408) that flanks a beta-barrel (referred to as the KOW module in MTR4 homologues). This entry represents the beta-barrel of Ski2 which does not have the KOW motif and is tightly packed against the helical stalk [1,2].

1: Structural analysis reveals the characteristic features of Mtr4, a DExH helicase involved in nuclear RNA processing and surveillance. Weir JR, Bonneau F, Hentschel J, Conti E; Proc Natl Acad Sci U S A. 2010;107:12139-12144. PMID:20566885

2: The crystal structure of S. cerevisiae Ski2, a DExH helicase associated with the cytoplasmic functions of the exosome. Halbach F, Rode M, Conti E; RNA. 2012;18:124-134. PMID:22114319