FIG. 4.
Sliding-window analysis of S. pneumoniae pbp2x PASTA domain 1 compared to the same domain of 27 other firmicute pbp2x orthologs. The corresponding protein structure (black bars, α-helix; gray bars, β-sheet) drawn to scale is shown above the graph, together with the S. pneumoniae PBP2x amino acid sequence alignment. Amino acids residues implicated in interactions with cefuroxime are denoted by asterisks, and residues shown in boldface are mutated in penicillin-resistant isolates. Amino acids shown in gray are not included in the sliding window analysis since they correspond to gaps in the alignment. The sliding-window analysis starts at position 18 due to “overhanging” amino acids from other sequences in the alignment.