Figure 1. Molecular architecture of the LytB glucosaminidase from S. pneumoniae R6.

(a) Scheme of LytB domain composition. Red hexagon represents the GH73 domain (LytB_GH73), yellow and salmon ellipses the SH3b (LytB_SH3b) and WW (LytB_WW) domains, respectively, which conform LytB_CAT. Blue rectangles represent the CBRs of the CBD domain (LytB_CBD). Numbers indicate the beginning and the end of each domain. (b) Cartoon representation of LytB_CAT comprising LytB_GH73, LytB_WW and LytB_SH3b domains coloured in red, salmon and yellow, respectively. Acidic residues mutated to alanine are shown in stick representation except for Asp607 which is located in the flexible region of LytB_GH73 and does not appear the X-ray structure (carbon atoms in blue, oxygen in red and nitrogen in blue). Non substituted acidic residues of LytB_CAT located out of the substrate binding groove are depicted in with carbon atoms in green.