Clustal alignment of the carboxytermini of black fly salivary 5' nucleotidases/apyrase compared with mammalian enzymes. The Simulium guianense protein (Sg-354) and black fly homologs are compared with the human and bovine sequences. The box shows the deletion of the membrane anchor region in the salivary apyrases of black flies. The symbols above the alignment indicate (*) identical sites; (:) conserved sites, and (.) less-conserved sites. For other details, see Figure 3.