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. |