Is there a unique ribosome phenotype for naturally occurring Escherichia coli?

We have compared the growth characteristics of natural isolates of E coli with the kinetic properties of their ribosomes in vitro. The variability of the different performance characteristics of ribosomes isolated from natural isolates of E coli show that there is not a unique wild-type ribosome phenotype just as there is not a unique growth phenotype for the bacteria. In addition, there is a strong correlation between the growth rates and the efficiency of the kinetic interaction between the ribosomes and the EF-Tu-GTP-aminoacyl-tRNA ternary complex in vitro. No such correlation is seen between the growth rate and the maximum turnover rate of the ribosomes in vitro. These data suggest that the codon-programmed ribosomes are not kinetically saturated with ternary complexes in vivo.