TABLE 1.

Bacterial strains and plasmids used in this study

Strain or plasmidRelevant characteristic(s)Source or reference
Strains
    E. coli
        BL21(DE3)galcIts857 ind1 Sam7 nin5 lacUV5-T7 gene 1)Novagen
        DH5αsupE44 ΔlacU169 (φ80 lacZΔM15)Gibco BRL
        XL1-BluerelA1 lac [F′ proAB laclqZΔM15 Tn10 (Tetr)]Stratagene
    S. pneumoniae
        CP1200Nonencapsulated derivative of Rx1; malM511 str-1Choi et al. (6)
        HYK2CP1200 ΔclpP::ermBKwon et al. (15)
        D39Encapsulated; type 2Avery et al. (1)
        HYK302D39 ΔclpP::ermBKwon et al. (15)
Plasmids
    pET30(a)5.4 kb; AprNovagen
    pKHY0026.0 kb; histidine-tagged clpP in pET30(a)This study