Bacterial host strain comprising a mutant SPR gene and having reduced TSP activity

摘要

The present invention provides a recombinant gram-negative bacterial cell comprising a mutant spr gene encoding a spr protein having a mutation at one or more amino acids selected from D133, H145, H157, N31, R62, I70, Q73, C94, S95, V98, Q99, R100, L108, Y115, V135, L136, G140, R144 and G147 and wherein the cell has reduced Tsp protein activity compared to a wild-type cell.

主权项

1. A recombinant gram-negative bacterial cell comprising:
a mutant spr gene that encodes a mutant spr protein having a mutation that is an amino acid substitution at one or more amino acids within the spr protein selected from the group consisting of D133, H145, H157, N31, R62, I70, Q73, C94, S95, V98, Q99, R100, L108, Y115, V135, L136, G140, R144, and G147, wherein the wild type spr protein has the sequence of SEQ ID NO: 21, and a mutation in the Tsp gene that encodes a mutated Tsp protein having reduced protease activity or a mutation in the Tsp gene or regulatory sequence of the Tsp gene that reduces or eliminates expression of the Tsp protein, wherein said mutant spr protein reduces lysis of cells containing the mutated Tsp gene.