Figure 7. Stk is involved in purine biosynthesis in S. epidermidis.

A. Growth curve of S. epidermidis 1457 WT and the isogenic stk mutant. Growth was determined by measuring OD₆₀₀ of cell cultures grown in RPMI 1640 synthetic medium at 37°C with or without addition of 200 µM adenine (Ade). B. Growth curves of stk mutant strains with different complementation plasmids: pQG71 (stk full length), pQG72 (stk kinase domain), pQG74 (stk PASTA repeated domain), pQG75 (stk C-terminal domain), pQG76 (stk kinase domain without ATP-binding site). Cell growth was monitored at OD₆₀₀ in RPMI 1640 synthetic medium at 37°C. C. Expression levels of purA was determined in samples prepared from exponential-phase (OD₆₀₀ = 0.5) cells grown in BM, using quantitative RT-PCR. Data were derived from three biological repeats. *, P<0.05 (versus WT).