This presumed domain has been predicted to contain three alpha helices. The domain was named the WIYLD domain based on the pattern of most conserved residues [1]. It binds ubiquitin. In the Arabidopsis thaliana histone-lysine N-methyltransferase SUVR4, Swiss:Q8W595, binding of ubiquitin to this domain stimulates enzymatic activity and converts its activity from a strict dimethylase to a di/trimethylase [2].

1: The Arabidopsis SUVR4 protein is a nucleolar histone methyltransferase with preference for monomethylated H3K9. Thorstensen T, Fischer A, Sandvik SV, Johnsen SS, Grini PE, Reuter G, Aalen RB; Nucleic Acids Res. 2006;34:5461-5470. PMID:17020925

2: The SUVR4 Histone Lysine Methyltransferase Binds Ubiquitin and Converts H3K9me1 to H3K9me3 on Transposon Chromatin in Arabidopsis. Veiseth SV, Rahman MA, Yap KL, Fischer A, Egge-Jacobsen W, Reuter G, Zhou MM, Aalen RB, Thorstensen T; PLoS Genet. 2011;7:e1001325. PMID:21423664