What does tRNA do, and what does “availability rate” mean?
In the protein translation process within cells, tRNA carries an amino acid that corresponds to a given codon. Different types of tRNA are used at varying frequencies during translation.
The concept of tRNA availability is key to the technology discussed here. The availability rate of tRNA corresponding to the codon AAA, for example, represents the ratio of tRNA (corresponding to the codon AAA) gene number to the frequency of codon AAA that appears in all coded genes in the genome.
Figure 2 shows the availability rates of tRNA in host microorganisms commonly used in industrial production. Importantly, high-availability tRNA differs from species to species.