Table 1. S. pyogenes strains used in this study.

Strain	Genotype
GAS-M1	emm1 strain (H305), wild type for smeZ
GAS-M1ΔsmeZ	smeZ gene disruption in GAS-M1
GAS-M1ΔsmeZsmeZ -M89	GAS-M1ΔsmeZ over-expressing functional SMEZ from GAS-M89
GAS-M1ΔsmeZsmeZ -M3	GAS-M1ΔsmeZ over-expressing M3-type SMEZ (which contains a 13 bp deletion)
GAS-M1control	GAS-M1 transformed with empty shuttle plasmid
GAS-M89	emm89 strain (H293), functional smeZ (smeZ-13 allele)
GAS-M89ΔsmeZ	smeZ gene disruption in GAS-M89 strain (H377)
GAS-M89ΔsmeZsmeZ -M89	GAS-M89ΔsmeZ over-expressing functional SMEZ from GAS-M89
GAS-M89ΔsmeZsmeZ -M3	GAS-M89ΔsmeZ over-expressing M3-type SMEZ (which contains 13 bp deletion)
GAS-M89control	GAS-M89 transformed with empty shuttle plasmid
GAS-M3	emm3 strain with M3-smeZ (which contains a 13 bp deletion) (H471)
GAS-M3smeZ -M89	GAS-M3 over-expressing functional SMEZ from GAS-M89
GAS-M3smeZ -M3	GAS-M3 over-expressing M3-type SMEZ which contains a 13 bp deletion)
GAS-M3control	GAS-M3 transformed with empty shuttle plasmid