Practice question

High-level expression of heterologous proteins at 37°C in Escherichia coli under strong promoters like T7 drives rapid polypeptide synthesis exceeding the capacity of endogenous chaperone systems such as GroEL-GroES and DnaK. Hydrophobic stretches improperly exposed interact intermolecularly, forming insoluble aggregates termed inclusion bodies sequestered in cytoplasm. Although protein is abundant, it is misfolded and functionally inactive. This aggregation is temperature and induction rate dependent rather than due to promoter absence, inducer failure, or cytotoxicity, and can be mitigated by lowering culture temperature or using solubility tags.