A classification of nucleotide-diphospho-sugar glycosyltransferases based on amino acid sequence similarities

The authors have informed us that, in the above paper, several polypeptide GalNAc transferases were listed as part of family 2, i.e. a family of inverting enzymes.However, these enzymes transfer GalNAc from UDP-GalNAc to Ser or Thr residues forming an α linkage.They are therefore retaining enzymes and, on this basis, they should be removed from family 2 and grouped in a new family (family 27) of retaining nucleotide-diphosphosugar glycosyltransferases.It is important to point out that the sequences of family 27 members display limited similarities with those of enzymes from family 2. It is therefore possible that these two families share some structural similarities.The composition of family 27 is given in the table below.