FIGURE 3.

The E. coli wt and S88L-trmD alleles. A, the operon structure harboring wt-trmD-Kan or S88L-trmD-Kan. The operon consists of four genes in the order of rpsP (the ribosomal protein S16), rimM (a 21-kDa protein that processes 16 S rRNA), trmD, and rplS (the ribosomal protein L19). A Kan-resistant cassette containing wt-trmD-Kan or S88L-trmD-Kan was introduced to replace the chromosomal trmD in the operon. B, growth analysis by a dilution series. E. coli cells harboring wt-trmD-Kan or S88L-trmD-Kan were spotted on an LB-Kan plate (Kan at 50 μg/ml) through serial dilutions and incubated at 30 or 43 °C overnight.