TABLE 1.

Strains and plasmids used in this work

Bacterial strain or plasmid	Description	Source or reference
E. coli XL1-Blue	recA1 endA1 gyrA96 thi-1 hsdr17 supE44 relA1 lac[F′ proAb lac1qZΔM15Tn10(TetI)]	3
S. lividans 1326	Host in transformation experiments	12
S. clavuligerus 27064	Producer of cephamycin C and clavulanic acid	ATCCa
S. clavuligerus(pB17B)	Transformant carrying ccaR in multicopy	27
S. clavuligerus ccaR::aph	ccaR-disrupted mutant	27
pBluescript I KS(+), pBluescript II SK(+)	E. coli general cloning vectors; Ampr	Stratagene
pQE30	Expression vector to purify histidine-tagged proteins; Ampr	Qiagen
pQE30-ccaR	pQE30 containing ccaR	This work
pIJ4083	Promoter-probe plasmid using xylE as reporter	6
pIJ6021	Used to get a 550-bp BamHI-KpnI fragment carrying the tipA promoter and the to terminator	7
pIJ699	Bifunctional E. coli/Streptomyces positive selection vector; 9.5 kb; Kanr Vphr Tsrr	12
pULVK99	Bifunctional E. coli/Streptomyces positive selection vector; 7.8 kb; Kanr Tsrr	4
pIK	Bifunctional plasmid obtained by ligation of pBluescript II SK(+) and pIJ4083	This work
pKTK	Intermediate vector; 4.9 kb; contains in pIJ699 sequentially the aph gene, the PtipA promoter, and the to terminator	This work
pKTCK	Intermediate vector; 5.75 kb; contains in pIJ699 sequentially the aph gene, the to terminator, the PtipA promoter, and the ccaR gene	This work
pCX	Intermediate vector; 4.8 kb; contains in pIJ699 sequentially the PccaR promoter, the xylE gene, and the to terminator	This work
pIKT, pCXT, pCXTccaR, pBXT-D and -I, pBXTccaR-D and -I	pIJ699-derived plasmids containing the inserts shown in Fig. 3	This work
PccaR-234	pULVK99-derived plasmid; 8 kb; carries in the EcoRI site a 234-nt DNA fragment containing the ccaR promoter	This work

^aATCC, American Type Culture Collection.