Figure 1

Multiple sequence alignment of ST3Gals (Table 1) obtained from the Tcoffee server [41]. A hyphen (" - ") indicates a one-residue gap. The ruler at the top is for the entire alignment and has no reference to any individual sequence; the latter are numbered on the right. The residues constituting the various motifs are marked below: L-motif (alignment position 173–216, denoted by *), linkage-specific motifs (219–227, denoted by & and 248–255, denoted by #), S-motif (321–343, denoted by @), motif III (356–359, denoted by %) and VS-motif (373–378, denoted by +). The structural and functionally important residues identified by mutation studies (Table 2) have been highlighted in red with bold font. Confidence is the confidence score given by Tcoffee. The regions having the same secondary structure in all the ST3Gals are also shown (marked cons-sec for consensus secondary structure). The names of the various strands and helices, indicated below the consensus secondary structure, are the same as those of the corresponding regions in CstII [13]. Residues highlighted in yellow and cyan constitute α-helices and β-strands, respectively, (as identified by SwissPDBviewer/RasMol) in at least one of the top models. The conserved cysteine residue in the stem region is highlighted in pink.