Table 1.

E. coli recipient and donor strains used in this study

StrainGenotype; phenotypeSource or reference
Recipients
 ZK126W3110 tna2 ΔlacU169; G08
 ZK819ZK126 rpoS819 rpsL; Smr, GI43
 ZK1141ZK819 lrp-1141 sgaA sgaC; GII41
 ZK2552ZK819 ilvGMEDA+; Valr44
 ZK2553ZK819bgl+; Bgl+44
Donors
 ZK1240ZK126cydC(surB1)::miniTn10Kmr35
 ZK2621ZK126sdaA94::Tn10CmrThis studya
 BE2W3110lrp-35::Tn10R. G. Matthews (10)
 BE3479PS2209gltB(psiQ32)::lacZ (Mu d1-1734)R. G. Matthews (10)
 CAG18467MG1655zfd-1::Tn1036
 CAG18493MG1655zbi-29::Tn1036
 DL39GλaspC13 fnr-25 glyA42::Tn5 ilvE12 tyrB507E. coli Genetic Stock Center, Yale University
 EC1051dadA279::Mu (Aprlac) araD139 ΔlacU169 met1 thi trp strAM. Freundlich (28)
  • a ThesdaA94::Tn10Cmr insertion mutation was isolated by random insertional mutagenesis of strain ZK126 with λNK1324 (23) and screening among the Cmrmutants for those that could not grow on serine as described elsewhere (37). The Tn10Cmr insertion of this mutant was mapped by arbitrary PCR (5, 44) to the middle ofsdaA (nucleotide 654 of 1365). Mutants with this allele showed only background level of L-SD activity (1.4 ± 7.4 versus 121 ± 21 mg of pyruvate formed min−1OD600−1 for ZK126 [18]).