FIGURE 1.
Alignment of vertebrate and candidate invertebrate ssSPTs. A, vertebrate ssSPTs are predicted by hydropathy analysis to have two TMDs. Shown in the alignment are members of the ssSPTa and ssSPTb subfamilies from Homo sapiens (hssSPTa or hssSPTb), Gallus domesticus (chick), Xenopus laevis (xenopus) and Danio rerio (zebrafish). hssSPTa is aligned and numbered without its three N-terminal residues (MAG) that the other vertebrate ssSPTa subunits lack. B, in contrast to the vertebrate ssSPTs, candidate invertebrate ssSPTs including the Drosophila melanogaster (cg32038) and Arabidopsis thaliana (At2g30942) ssSPTs are predicted to have only one TMD.