Complementation of a proBA mutation
by tomPRO1 and tomPRO2, and their
products expressed in E. coli. A and B, Expression
vectors containing the tomPRO1 and
tomPRO2 cDNA clones were introduced into strain KC1325
(a derivative of BL21[DL3]pLysS carrying the
proB1658::Tn10 insertion, which
is polar on proA). a, KC1325 harboring the vector, pKS
only. b, KC1325 harboring pPRO1. c, KC1325 harboring pET32a only. d,
KC1325 harboring pET32PRO2. Strain KC1325 containing each plasmid was
streaked on minimal M63 medium containing Glc, thiamine, and IPTG with
(A) and without (B) Pro, and incubated for 2 d at 37°C. All
strains could grow on the media supplemented with Pro (A). C, Total
cell extracts from either E. coli strain HB101,
containing pKS (lane 1) and pPRO1 (lane 2), or strain KC1325,
containing pET32a (lane 3) and pET32PRO2 (lane 4), were analyzed by
SDS-PAGE. The gels were stained with Coomasie brilliant blue.
tomPRO1 products are indicated as GK and GPR, and the
tomPRO2 product as P5CS. Numbers at left refer to size
standards (in kD).