Comparative genomics and experimental evolution of Escherichia coli BL21(DE3) strains reveal the landscape of toxicity escape from membrane protein overproduction

Citations Over TimeTop 10% of 2015 papers

Abstract

Achieving sufficient yields of proteins in their functional form represents the first bottleneck in contemporary bioscience and biotechnology. To accomplish successful overexpression of membrane proteins in a workhorse organism such as E. coli, defined and rational optimization strategies based on an understanding of the genetic background of the toxicity-escape mechanism are desirable. To this end, we sequenced the genomes of E. coli C41(DE3) and its derivative C43(DE3), which were developed for membrane protein production. Comparative analysis of their genomes with those of their ancestral strain E. coli BL21(DE3) revealed various genetic changes in both strains. A series of E. coli variants that are able to tolerate transformation with or overexpression of membrane proteins were generated by in vitro evolution. Targeted sequencing of the evolved strains revealed the mutational hotspots among the acquired genetic changes. By these combinatorial approaches, we found non-synonymous changes in the lac repressor gene of the lac operon as well as nucleotide substitutions in the lacUV5 promoter of the DE3 region, by which the toxic effect to the host caused by overexpression of membrane proteins could be relieved. A mutation in lacI was demonstrated to be crucial for conferring tolerance to membrane protein overexpression.

Related Papers

• → Establishment of a low‐dosage‐IPTG inducible expression system construction method in Escherichia coli(2018)12 cited
• → Inducible expression of bcl-2 by the lac operator/repressor system in MDCK cells(1997)13 cited
• → Expression of Cloned Genes in E. coli Using IPTG-Inducible Promoters(2021)15 cited
• Prospect of the Lac Operon Mediated Galactosidase Applied in Transgenic Animals(2010)
• Inducible expression of bcl-2 by the lac operator/repressor system in MDCK cells(1997)