High-level accumulation of a recombinant antibody fragment in the periplasm of Escherichia coli requires a triple-mutant (degP prc spr) host strain.
During production of a humanized antibody fragment secreted into the periplasm of Escherichia coli, proteolytic degradation of the light chain was observed. In order to determine which protease(s) were responsible for this degradation, we compared expression of the F(ab')(2) antibody fragment in several E. coli strains carrying mutations in genes encoding periplasmic proteases. Analysis of strains cultured in high cell density fermentations showed that the combination of mutations in degP prc spr was necessary for the cells to produce high levels of the desired recombinant antibody fragment. In order to eliminate the possible effects of mutations in other genes, we constructed E. coli strains with protease mutations in isogenic backgrounds and repeated the studies in high cell density fermentations. Extensive light chain proteolysis persisted in degP strains. However, light chain proteolysis was substantially decreased in prc and prc spr strains, and was further decreased with the introduction of a degP mutation in prc and prc spr mutant strains. These results show that the periplasmic protease Prc (Tsp) is primarily responsible for proteolytic degradation of the light chain during expression of a recombinant antibody fragment in E. coli, and that DegP (HtrA) makes a minor contribution to this degradation as well. The results also show that spr, a suppressor of growth defects in prc strains, is required for a prc mutant to survive throughout high cell density fermentations.
Chen
Christina
C
Department of Cell Culture and Fermentation Research and Development, Genentech, Inc., South San Francisco, California 94080, USA. kmc@gene.com
Snedecor
Brad
B
Nishihara
Julie C
JC
Joly
John C
JC
McFarland
Nancy
N
Andersen
Dana C
DC
Battersby
John E
JE
Champion
Kathleen M
KM
D018821:CD18 Antigens / Q000276:immunology; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division; D002470:Cell Survival; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D007128:Immunoglobulin Fragments / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D016297:Mutagenesis, Site-Directed; D019897:Periplasm / Q000378:metabolism; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000096:biosynthesis; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity
D018821:CD18 Antigens; D006360:Heat-Shock Proteins; D007128:Immunoglobulin Fragments; D033903:Periplasmic Proteins; D011994:Recombinant Proteins; D010450:Endopeptidases; C061682:DegP protease; D012697:Serine Endopeptidases; C072135:C-terminal processing peptidase