Co-production of GroELS discriminates between intrinsic and thermally-induced recombinant protein aggregation during substrate quality control.

Background: The effects and effectiveness of the chaperone pair GroELS on the yield and quality of recombinant polypeptides produced in Escherichia coli are matter of controversy, as the reported activities of this complex are not always consistent and eventually indicate undesired side effects. The divergence in the reported data could be due, at least partially, to different experimental conditions in independent research approaches.

Results: We have then selected two structurally different model proteins (namely GFP and E.

Protein aggregation and soluble aggregate formation screened by a fast microdialysis assay.

Protein aggregation is a major obstacle in recombinant protein production as it reduces the yield of soluble polypeptides. Also, the formation of aggregates occurring in the soluble fraction is more common than formerly expected, and the prevalence of these entities might significantly affect the average quality of the soluble protein species. Usually, the formation of soluble aggregates remains unperceived because analytical methods such as dynamic light scattering are not routinely applied as quality control procedures.