Fig. 3.

Pairwise HMM logo (Schuster-Bockler and Bateman, 2005) of protein families PF02021 and PF03008 from Pfam 23.0 (Finn et al., 2008). PF02021 is annotated as a member of the PD-(D/E)xK clan (CL0236), while PF03008 (also known as DUF234) has no informative annotation. Despite low sequence identity, the alignment of conserved acidic residues and the lysine which are required for catalysis (Aravind et al., 2000; Knizewski et al., 2007) supports their relationship; it is also strongly supported by HHsvm4 (Supplementary Table 2).