Fig. 5: Evolution of camSOD coincided with expansion of virulence factor network.

a Circular genome alignment comparing 29 analyzed staphylococcal genomes, using S. aureus strain NCTC8325 as reference genome. The sodA gene (yellow), encoding MnSOD, is located in a genomic region enriched in essential genes (blue) that is highly conserved across the staphylococci, whereas the sodM gene (orange), encoding camSOD, is located in a variable genomic region enriched in virulence factors (green). b Expanded view of the local genomic context of the sodA (upper panel) and sodM (lower panel) genes. c Heatmap depicting the results from analysis of protein similarity networks, which identified protein families whose copy numbers (see color key) have been altered during evolution of the staphylococci (see phylogenetic tree in the upper panel). Protein families are represented on horizontal lines, and are grouped as Identified in all (black), Not identified in S. aureus (gray), S. aureus-specific (red), Enriched in S. aureus (orange) as described in the Methods. Genes inferred to be essential in analyzed S. aureus genomes are illustrated by blue bars. The lower panel illustrates the amino acid residues present at positions 19, 159, and 160 of each SOD isozyme present in the respective genome.