Extracellular recombinant protein production from an Escherichia coli lpp deletion mutant.
E. coli is one of the most commonly used host strains for recombinant protein production. However, recombinant proteins are usually found intracellularly, in either cytoplasm or periplasmic space. Inadequate secretion to the extracellular environment is one of its limitations. This study addresses the outer membrane barrier for the translocation of recombinant protein directed to the periplasmic space. Specifically, using recombinant maltose binding protein (MalE), xylanase, and cellulase as model proteins, we investigated whether the lpp deletion could render the outer membrane permeable enough to allow extracellular protein production. In each case, significantly higher excretion of recombinant protein was observed with the lpp deletion mutant. Up to 90% of the recombinant xylanase activity and 70% of recombinant cellulase activity were found in the culture medium with the deletion mutant, whereas only 40-50% of the xylanase and cellulase activities were extracellular for the control strain. Despite the weakened outer membrane in the mutant strain, cell lysis did not occur, and increased excretion of periplasmic protein was not due to cell lysis. The lpp deletion is a simple method to generate an E. coli strain to effect significant extracellular protein production. The phenotype of extracellular protein production without cell lysis is useful in many biotechnological applications, such as bioremediation and plant biomass conversion.
Shin
Hyun-Dong
HD
School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100, USA.
Chen
Rachel R
RR
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002480:Cellulase / Q000235:genetics / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D043364:Endo-1,4-beta Xylanases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics*; D017353:Gene Deletion; D008074:Lipoproteins / Q000235:genetics*; D058619:Maltose-Binding Proteins; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C099932:Lpp protein, E coli; D058619:Maltose-Binding Proteins; D011994:Recombinant Proteins; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases