The multiple sequence alignment used for homology modeling of the TfHex monomer. Active site amino acids are marked by red dots. Cysteine residues are marked by green dots. Active site amino acids are numbered according to the sequence of β-N-acetylhexosaminidase from T. flavus (TfHex). 1jak - hexosaminidase from bacteria Streptomyces plicatus; 1now - human HexB; 3nsn - hexosaminidase from insect Ostrinia furnacalis. Val 276 in S. plicatus hexosaminidase is shown by red box.