Figure 3

Human sphingomyelinase or bacterial isochorismate synthase? The sequence AAF19052 is reported to be a human neutral sphingomyelinase, containing a DEATH domain at the C-terminus. The top panel shows the PFAM domain architecture, which reveals the presence of a chorismate-binding domain at the C-terminus and the absence of a DEATH domain. The lower panel displays a structural phylogenomic analysis, resulting from clustering the sequence homologs to AAF19052 using FlowerPower and construction of a Maximum Parsimony tree. Examination of the phylogenetic tree suggests that AAF19052 (red box) is more likely an isochorismate synthase of bacterial origin. Each node in the tree is labeled with the species of origin, SCI-PHY subfamily label (see Methods), and sequence identifier and definition line.