Conserved DXD motifs in families of glycosyltransferases. Known families of glycosyltransferases were initially aligned by using blast. Where a DXD motif is conserved, the regions surrounding it were aligned with clustal. Residues identical (black) or related (gray) in a majority of the family are boxed. Species are indicated as: At, Arabidopsis thaliana; Ce, Caenorhabditis elegans; Cf, Canis familiaris; Dd, Dictyostelium discoideum; Ec, Escherichia coli; Gg, Gallus gallus; Hp, Helicobacter pylori; Hs, Homo sapiens; Ls, Lymnaea stagnalis; Mm, Mus musculus; Ng, Neisseria gonorrhoeae; Rl, Rhizobium leguminosarum; Rn, Rattus norvegicus; Sc, S. cerevisiae; Sm, Schistosoma mansoni; Sp, Sch. pombe; Ss, Synechocystis sp.; St, Salmonella typhimurium; Tb, Trypanosoma brucei. The members of the cellulose synthase superfamily are: Acetobacter xylinus cellulose synthase acsAB (acsA); Gossypium hirsutum cellulose synthase A (CelA); Hs hyaluronan synthase 1 (Hyl); Streptococcus thermophilus epsI (EpsI); Hs N-acetylgalactosaminyltransferase I (GNAc); and Sc chitin synthase 1 (CHS1).