Bacterial host strain comprising a mutant spr gene and a wild-type Tsp gene

摘要

The present invention provides a recombinant gram-negative bacterial cell comprising a mutant spr gene encoding a mutant spr protein and wherein the cell comprises a non-recombinant wild-type chromosomal Tsp gene.

主权项

1. A recombinant gram-negative bacterial cell comprising a mutant spr gene encoding a mutant spr protein containing a mutation that is an amino acid substitution at one or more amino acids within the spr protein, wherein the cell comprises a non-recombinant wild-type chromosomal Tsp gene, wherein expression of said mutant spr gene causes the cell to exhibit increased yield of a recombinant protein of interest or reduced lysis as compared to wild-type bacterial cells expressing a protein of interest and the genome of the cell is isogenic to the wild-type bacterial cell except for the mutated spr gene and, optionally, one or more of:
a) a mutated DegP gene encoding a DegP protein having chaperone activity and reduced protease activity; b) a mutated ptr gene, wherein the mutated ptr gene encodes a Protease III protein having reduced protease activity or is a knockout mutated ptr gene; c) a mutated OmpT gene, wherein the mutated OmpT gene encodes an OmpT protein having reduced protease activity or is a knockout mutated OmpT gene; d) a recombinant polynucleotide encoding DsbC; and e) a polynucleotide encoding a protein of interest.