Canonical T7SS substrate EsxA is conserved across T7SSa and T7SSb loci.

a) ClustalW alignments and percent identity matrix of EsxA protein sequences from Mtb (H37Rv; accession CP003248.2), E. faecalis (OG1RF; accession CP002621.1), S. intermedius (B196; accession NC_022246.1), B. subtilis (PY79; accession NC_022898.1), L. monocytogenes (EGD-e; accession NZ_CP023861.1), S. aureus (USA300 FPR3757; accession NC_007793.1), S. gallolyticus (TX20005; accession AEEM00000000.1), S. agalactiae (CJB111; accession CP063198.2) and S. suis (GZ0565; accession NZ_CP017142.1). In the above matrix, the purple shading corresponds to the level of identity between two strains (on a spectrum of 0 to 100% identity), with darker shading indicative of higher percent identity. b) Western blot showing EssC-dependent secretion of EsxA from GBS, in vitro. Blots pictured are representative of 3 independent experiments. The un-cropped Western blot as well as the Coomassie stained gel can be found in S3B and S3C Fig.