Fig. 8

Alignment of the amino acid sequences of mouse ExtL2 (NP_001156986) and human EXT1 (NP_000118). Homologies are boxed and shaded according to identity (dark grey) and similarity (light grey). Although the two EXT proteins do not show much sequence homology, most of the critical amino acid residues, which are known to interact with the catalytic manganese ion and the UDP-sugar, are conserved (marked in red). The sequence encoded by exon 8 of the human EXT1 gene is given in brackets. It harbors the DXD signature (indicated by three asterisks) present in all UDP-dependent glycosyltransferases as well as a critical arginine residue that forms a hydrogen bond with the donor sugar