Active Inclusion Bodies Protect the Target Protein from Degradation in Escherichia coli Cells

The production of target proteins in Escherichia coli cells can be greatly simplified if they are synthesized in a biologically active state as part of active inclusion bodies (AIBs), which can easily be isolated from cells by centrifugation. This is a new technology, so the question about the protective properties of AIBs specific for standard inclusion bodies still remains open. This work describes the synthesis of the recombinant protein L₆KD-SUMO-[R³⁴-GLP-1(7–37)], which forms AIB, in E. coli BL21(DE3) cells. This protein engineered from a novel, recently developed L₆KD-SUMO platform incorporates a modified human glucagon-like peptide-1, R³⁴-GLP-1(7–37), the active substance of Liraglutide-based drugs. It was shown that, the soluble protein His₁₀-SUMO-[R³⁴-GLP-1(7–37)] expressed by E. coli, retained the peptide intact only for 24 h, but the peptide integrity in the AIB composition was maintained over 70 h of cell cultivation. Thus, it is logical to assume that AIB formation has a protective effect on target compounds synthesized by the cell.