Phylogram of ScULP1-like proteins. Arabidopsis proteins that exhibit at least 40% conserved residues when compared with the catalytic domain of ScULP1, as well as Senp1 to 3, Senp5 to 7, Den1, XopD, and ScULP1, were grouped into a phylogenetic tree using the ClustalW server at the University of Wageningen (www.bioinformatics.nl/tools/clustalw.html) with standard settings. Bootstrap values (1,000 replicates) are shown at the branches.