Table 1 Bacterial strains and plasmids used in this study

S. mutans

UA159

Wild type, the genome sequence reference strain

48

XT-D1

UA159 ∆comX::spec, Spec^r

34

XT-D3

UA159 ∆mecA::erm, Erm^r

34

XT-D4

UA159 ∆mecA::spec, Spec^r

34

XT-D7

UA159 ∆clpC::kan, Kan^r

This study

XT-D8

UA159 ∆clpP::kan, Kan^r

This study

XT-Lx1

UA159 carrying pWAR304, Em^r ,

34

XT-His1

UA159 carrying pSigX-His, Spec^r

34

XT-His2

XT-D3 carrying pSigX-His, Em^r , Spec^r

34

XT-His3

XT-D7 carrying pSigX-His, Kan^r , Spec^r

34

GF-His1

XT-D8 carrying pSigX-His, Kan^r , Spec^r

This study

GF-His2

UA159 carrying pMecA-His, Spec^r

This study

GF-His3

UA159 carrying pClpC-His, Spec^r

This study

GF-His4

UA159 carrying pClpP-His, Spec^r

This study

GF-Ox

UA159 pDL277::Pldh-mecA-His, Spec^r

This study

E. coli

DH5α

Cloning host

Invitrogen

XL1-blue

Cloning host

Stratagene

BL21(DE3)

Recombinant protein expression strain

Novagen

BL21(DE3)pLysS

Recombinant protein expression strain

Novagen

Plasmids

pGEX-6P-1

E. coli expression vector (GST-tag), Amp^r

GE

pGF-SigX

pGEX-6P-1::comX, GST-tag fusion, Amp^r

This study

pGF-MecA

pGEX-6P-1::mecA, GST-tag fusion, Amp^r

This study

pGF-ClpC

pGEX-6P-1::clpC, GST-tag fusion, Amp^r

This study

pGF-ClpP

pGEX-6P-1::clpP, GST-tag fusion, Amp^r

This study

pET-20b(+)

E. coli expression vector (6His-tag), Amp^r

Novagen

pGF2-SigX

pET-20b::comX, His-tag fusion, Amp^r

This study

pGF2-MecA

pET-20b::mecA; His-tag fusion, Amp^r;

This study

pGF2-ClpC

pET-20b::clpC; His-tag fusion, Amp^r

This study

pGF2-ClpP

pET-20b::clpP; His-tag fusion, Amp^r

This study

pGF2-NTD

pET-20b::mecA _(aa1–82) , His-tag fusion, Amp^r;

This study

pGF2-CTD

pET-20b::mecA _{(aa123–240)} , His-tag fusion, Amp^r;

This study

pGF3-P + X

pET-20b::Promoter + comX, His-tag fusion, Amp^r

This study

pDL277

E. coli-Streptococcus shuttle vector, Spec^r

47

pSigX-His

pDL277::Promoter + comX-His, Spec^r

34

pGF3-PA

pET-20b::Promoter + mecA, His-tag fusion, Amp^r

This study

pMecA-His

pDL277::Promoter + mecA-His, Spec^r

This study

pGF3-PC

pET-20b::Promoter + clpC, His-tag fusion, Amp^r

This study

pClpC-His

pDL277::Promoter + clpC-His, Spec^r

This study

pGF3-PP

pET-20b::Promoter + clpP, His-tag fusion, Amp^r

This study

pClpP-His

pDL277::Promoter + clpP-His, Spec^r

This study

pXT-Pldh

pDL277::Promoter of ldh (Pldh), Spec^r

This study

pMecA-Ox

pXT-Pldh::MecA-His, Spec^r

This study

pWAR303

A shuttle vector containing promoterless luxAB, Em^r

18

pWAR304

pWAR303 having a fusion of PcomX::luxAB, Em^r

18