This is a novel knotted tudor domain which is required for binding to RNA. The know influences the loop conformation of the helical turn Ht2 - residues 61-6 3- that is located at the side opposite the knot in the tudor domain-chromodomain; stabilisation of Ht2 is essential for RNA binding [1].

1: Novel structural and functional mode of a knot essential for RNA binding activity of the Esa1 presumed chromodomain. Shimojo H, Sano N, Moriwaki Y, Okuda M, Horikoshi M, Nishimura Y; J Mol Biol. 2008;378:987-1001. PMID:18407291