Table 1

Strains and plasmids used in this study

Strain or plasmidRelevant characteristics or useReference or source
C. diphtheriae strains
    1737Wild type, Gravis biotype, Tox+37
    1737htaAΔhtaA deletion mutant of 173725
    1737htaBΔhtaB deletion mutant of 173725
    1737chtAΔchtA deletion mutant of 1737This study
    1737chtBΔchtB deletion mutant of 1737This study
    1737chtCΔchtC deletion mutant of 1737This study
    1737chtAΔ/chtBΔDeletion of chtA and chtB in 1737This study
    1737htaBΔ/chtBΔDeletion of htaB and chtB in 1737This study
    1737chtAΔ/chtCΔ/htaAΔDeletion of chtA, chtC, and htaA in 1737This study
    1737chtAΔ/chtCΔDeletion of chtA and chtC in 1737This study
    C7(−)Wild type, Tox38
    C7dtxRΔC7 dtxR deletion mutant25
E. coli strains
    BL21(DE3)Protein expressionNovagen
    DH5αCloning strainInvitrogen
    S17-1RP4 mobilization functions32
    TOP10Cloning of PCR fragmentsInvitrogen
    XL1-GoldMutagenesis strainStratagene
Plasmids
    pCR-Blunt-IITOPOCloning of PCR fragments, KnrInvitrogen
    pSPZPromoter probe, Spcr28
    pGEX-6P-1Expression vector (GST fusion), AmprGE Healthcare
    pET24(a)+Expression vector, KnrMillipore
    pKN2.6ZC. diphtheriae shuttle vector, Knr24
    pKhtaApKN2.6Z carrying the htaA gene25