Table 2. Plasmids and strains used and the associated literature source.

Strains/plasmid	Description	Source/Reference
E.coli strain M15pREP4	Expression host containing pREP4; kanamycin resistant	Qiagen
pQE30	IPTG inducible expression vector. Introduces RGS(H)6 at the N terminus of the expressed protein. Confers ampicillin resistance	Qiagen
pQE60	IPTG inducible expression vector. Introduces RGS(H)6 at the C terminus of the expressed protein. Confers ampicillin resistance	Qiagen
pQE60A3P1	CheA3P1 expression plasmid. pQE60 derivative	[7]
pQEY6	CheY6 expression plasmid. pQE30 derivative	[24]
pQEA3	CheA3 expression plasmid. pQE30 derivative	[21]
pQEA4	CheA4 expression plasmid. pQE30 derivative	[21]