FIGURE 5.

Comparison of the GT-B domain of representative HMW1C-like proteins and OGT-like proteins, two subfamilies of GT41. A, structure-based sequence alignment of the GT-B domains. Residues involved in UDP binding and proposed to be involved in hexose moiety binding are marked with blue asterisks and pink diamonds, respectively. It is noticed that there is a large insertion in HsOGT and DmOGT between GT-1 and GT-2, as indicated in the blue box. Examples of N-glycosyltransferases include A. pleuropneumoniae HMW1C (Ap), H. influenzae HMW1C (Hi), E. coli EtpC (Ec), and Yersinia enterocolitica RcsC (Ye). Examples of O-glycosyltransferases include Homo sapiens OGT (Hs), Drosophila melanogaster OGT (Dm), Arabidopsis thaliana OGT (At), and Xanthomonas campestris OGT (Xc). B, structural comparison of ApHMW1C with GT-B adopting proteins, XcOGT (PDB 2JLB) and E. coli glycogen synthase (PDB 2R4T). The structures are shown in cartoon representation with color spectrum from blue (N terminus) to red (C terminus) for AAD and TPR, and GT-1 and GT-2 domains are in green and pink hues, respectively.