Codon Preference Optimization Increases Prokaryotic Cystatin C Expression
Gene expression is closely related to optimal vector-host system pairing in many prokaryotes. Redesign of the humancystatin C(cysC) gene using the preferred codons of the prokaryotic system may significantly increasecysCexpression inEscherichia coli(E. coli). Specifically,cysCexpression may be increased by removing unstable sequences and optimizing GC content. According toE. coliexpression system codon preferences, the gene sequence was optimized while the amino acid sequence was maintained. The codon-optimizedcysC(co-cysC) and wild-typecysC(wt-cysC) were expressed by cloning the genes into a pET-30a plasmid, thus transforming the recombinant plasmid intoE. coliBL21. Before and after the optimization process, the prokaryotic expression vector and host bacteria were examined for protein expression and biological activation of CysC. The recombinant proteins in the lysate of the transformed bacteria were purified using Ni2+-NTA resin. Recombinant protein expression increased from 10% to 46% based on total protein expression after codon optimization. Recombinant CysC purity was above 95%. The significant increase incysCexpression inE. coliexpression produced by codon optimization techniques may be applicable to commercial production systems.