Table 1 Bacterial strains and vectors used in this study

 DH5α

supE44 lacU169 (80lacZ M15) hsdR17 recA1 endA1 gyrA96 thi-1 relA1 luxS

(Hanahan 1983)

 BL21(DE3)pLysS

F ˉ ompT gal hsdSB (r_Bˉ m_Bˉ) dcm lon λDE3 pLysS

(Studier et al. 1990)

 BL21/p41ComE

BL21 (DE3) pLysS habouring p41ComE to express fusion protein GST-ComE, Kan^R

This work

 WT

Wild-type strain UA159, Kan^S Erm^S

(Ajdic et al. 2002)

 WT/pA-LacZ

WT with pA-lacZ by single cross insertion, Kan^R

This work

 ΔcomX/pA-LacZ

As WT/pA-LacZ but comX::erm, Kan^R Erm^R

This work

 ΔcomED/pA-LacZ

As WT/pA-LacZ but comED::erm, Kan^R Erm^R

This work

 ΔcomC/pA-LacZ

As WT/pA-LacZ but comC::erm, Kan^R Erm^R

This work

 WT/pC-LacZ

WT with pC-lacZ by single cross insertion, Kan^R

This work

 ΔcomX/pC-LacZ

As WT/pC-LacZ but comX::erm, Kan^R Erm^R

This work

 ΔcomED/pC-LacZ

As WT/pC-LacZ but comED::erm, Kan^R Erm^R

This work

 ΔcomC/pC-LacZ

As WT/pC-LacZ but comC::erm, Kan^R Erm^R

This work

 pUCm-T

Cloning T-vector, Amp^R

Sangon (SK2211)

 pET41a (+)

Expressing vector, Kan^R

Novagen (69337–3)

 p41ComE

pET41a (+) insterted by comE to express fusion protein GST-ComE, Kan^R

This work

 pSF151

Shuttle vector, Kan^R

(Tao et al. 1992)

 pLacZ

pSF151 habouring gene lacZ, Kan^R

This work

 pA-LacZ

pLacZ with the promoter of nlmAB to drive lacZ, Kan^R

This work

 pC-LacZ

pLacZ with the promoter of nlmC to drive lacZ, Kan^R

This work