Table 1. Strains and plasmids.

Strains	Description
MGAS2221	Clinical isolate, emm1, covRS wild type	[28]
2221ΔcovR	MGAS2221, ΔcovR:aphA3	[29]
2221-CovS-E281A	MGAS2221, exchange of glutamate at CovS position 281 to alanine	[30]
2221-CovR-D53A	MGAS2221, exchange of aspartate at CovR position 53 to alanine	[30]
E. coli DH5α	SupE44,ΔlacU109,(Φ80lacZΔM15), hsdR17, recA1,endA1,gqrA96, thi-1,relA1	[31]
Rosetta (DE3)/pLysS		Novagen
Plasmids
pET15b	Overexpression vector, N-terminal His6-tag, ampR	Novagen
pET15b-CovRND	Overexpression of CovR, N-terminal domain	this study
pJC306	luxAB transcriptional fusion, spec	gift from M. Federle
pJC306-hasA	hasA-luxAB transcriptional fusion	this study
pJC306-hasAmut	hasA-luxAB transcriptional fusion with mutation in putative CovR binding motif	this study
pJC306-spy_0187	spy_0187-luxAB transcriptional fusion	this study
pJC306-spy_0187mut	spy_0187-luxAB transcriptional fusion with mutation in putative CovR binding motif	this study
pJC306- spy_0187sp	spy_0187-luxAB transcriptional fusion, with 2bp insertion within putative CovR binding motif	this study