Solubility dependency of co-expression effects of stress-induced protein Dps on foreign protein expression in Escherichia coli

Abstract

The over-expression of foreign proteins imposes metabolic burden on host strains that may lead to reduced cell growth and even yield of target protein. We investigated dependency of co-expression effects of stress-induced non-specific DNA-binding protein, Dps, on cell growth and foreign protein expression according to solubility in Escherichia coli. Dps co-expression showed clear distinct effects according to solubility of target proteins. Under co-expression of recombinant Dps, cell growth for the strain expressing baculoviral polyhedrin (Polh)-green fluorescent protein (GFP) fusion protein or human interleukin-2 (hIL-2) that were expressed as insoluble inclusion body had tendency to decline slightly compared to each Dps non-expressing strain. However, cell growth for the strain expressing soluble GFP or Mussel adhesive protein type 5 (Mgfp-5) was somewhat increased. While Dps co-expression had somewhat negative effects on expression of soluble protein, it showed huge impacts on product yield of insoluble proteins (1.6-1.8-fold for Polh-GFP and 4-5-fold for hIL-2). Therefore, it was obvious that co-expression of Dps has different effects on foreign protein production according to solubility. Proteomic analyses revealed that Dps co-expression induced significantly different global patterns through interaction with target foreign protein according to target solubility. These global pattern alterations might be favorable for production of insoluble foreign proteins indirectly. (c) 2006 Elsevier Inc. All rights reserved.