TABLE 1.

Bacteria and plasmids

Strain or plasmidDescriptionaReference or source
Strains
    E. coli
        TG1supE hsdΔ5 thi Δ(lac-proAB) F′[traD36 proAB+ lacIq lacZΔM15]33
        HB101supE44 hdsS20(rβmβ) recA13 ara-14 proA2 lacY1 galK2 rpsL20 xyl-5 mtl-133
        M15(pREP4)A K-12-derived E. coli strain that carries plasmid pREP4; Nals Strs Rifs lac ara gal mtl F recA+ uvr+Qiagen, Inc.
    S. maltophilia
        D457From a bronchial aspirate4
        D457RSingle-step spontaneous SmeDEF-overproducing mutant derived from D4572, 4
Plasmids
    pLAFR3Low-copy-number cloning cosmid38
    pAS1pLAFR3 containing the smeDEF operon2
    pAS5pLAFR3 containing an S. maltophilia D457R genome fragment that overlaps with smeDEFThis study
    pGEMT-EasyApr, vector for cloning of PCR productsPromega
    pVLT31Tcr, RSF1010-laclq/Ptac hybrid broad-host-range expression vector, MCS of pUC1812
    pBluescript II KS(+)Apr, cloning vector33
    pPS1pVLT31 derivative plasmid that carries the wild-type smeT gene from D457This study
    pUJ8Apr, ori ColE1, tpr′-′lacZ promoter probe plasmid vector, lacZ fusions type I13
    pPS3PUJ8 derivative plasmid that carries a 224-pb EcoRI fragment containing PsmeDEF::lacZThis study
    pALTER-Ex2Tcr, ori p15aPromega
    pPS4PALTER-Ex2 derivative plasmid that carries wild-type smeT with its own promoter sequenceThis study
    pPS5pALTER-Ex2 derivative plasmid that carries L166Q smeT from S. maltophilia D457R with its own promoter sequenceThis study
    pQE31Expression vector to create fusion proteins tagged with the six-histidine tag, AprQiagen, Inc.
    pPREP4Plasmid that carries the lacI gene encoding the lac repressor; used to regulate expression of recombinant proteins tagged with the six-histidine tagQiagen, Inc.
    pPS6pQE31 derivative plasmid that carries a KpnI-PstI restriction fragment countering smeTThis study
    pRK600Cmr, ori ColE1, RK2-Tra+, helper plasmid in triparental mating21
  • a Km, kanamycin; Rif, rifampin; Ap, ampicillin; Cm, chloramphenicol; Tc, tetracycline; Nal, nalidixic acid; Str, streptomycin.