Figure 6.

The conserved Arg139 residue is needed for AglD activity, unlike the conserved Asp133 or Gly177 residues. Site-directed mutagenesis was performed to generate CBD-AglD containing mutations of Asp133, Arg139, and Gly177, as listed on the left of each panel. For each mutant, the upper and lower panels respectively show the Coomassie- and PAS-stained S-layer glycoprotein from the background strain (lanes 1 and 5), from the aglD deletion strain (lane 2), from the aglD deletion strain complemented with a plasmid encoding CBD-AglD (lane 3), or from the aglD deletion strain complemented with a plasmid encoding CBD fused to mutated AglD (lane 4).