Improvement of protein production by modulating the tRNA pool. For maximal heterologous expression of proteins per host cell, the optimal level of expression of genes needs to be addressed. The science and art of expressing a gene from one species in another often amounts to modifying the codons of the gene, and supplementing the host with specific tRNAs. Yet the full challenge of heterologous expression is not only to maximize expression per host cell, but also to minimize the burden on the host. The outlined invention describes a universally conserved profile of translation efficiency along mRNAs, based on the adaptation between coding sequences and the tRNA pool, to improve heterologous gene expression and thus protein production.
- Improvement of the yield and success rate of recombinant protein production.
- Protein expression levels can be artificially increased
- Minimization of the burden on the host
The translation efficiency profile of a gene is defined, for each codon position, as the estimated availability of the tRNAs that participate in translating that codon. The profile is high at codons that correspond to abundant tRNAs and low at codons that correspond to rare tRNAs. In this invention it is predicted that the first ~30-50 codons of genes appear to be translated with a low efficiency ramp, while the last ~50 codons show highest efficiency. The ramp serves as a late stage of initiation and is an optimal and robust means to reduce ribosomal traffic jams, thus minimizing occupation of free ribosomes, ribosomal abortions and, ultimately, the cost of protein expression. Implementation of appropriate ramping in heterlogous proteins, given the host?s tRNA pool, might improve the yield of expressed recombinant proteins.