A novel genetic system for recombinant protein secretion in the Antarctic Pseudoalteromonas haloplanktis TAC125.

Background: The final aim of recombinant protein production is both to have a high specific production rate and a high product quality. It was already shown that using cold-adapted bacteria as host vectors, some "intractable" proteins can be efficiently produced at temperature as low as 4 degrees C.

Results: A novel genetic system for the production and secretion of recombinant proteins in the Antarctic Gram-negative bacterium Pseudoalteromonas haloplanktis TAC125 was set up. This system aims at combining the low temperature recombinant product production with the advantages of extra-cellular protein targeting. The psychrophilic alpha-amylase from Pseudoalteromonas haloplanktis TAB23 was used as secretion carrier. Three chimerical proteins were produced by fusing intra-cellular proteins to C-terminus of the psychrophilic alpha-amylase and their secretion was analysed. Data reported in this paper demonstrate that all tested chimeras were translocated with a secretion yield always higher than 80%.

Conclusion: Data presented here demonstrate that the "cold" gene-expression system is efficient since the secretion yield of tested chimeras is always above 80%. These secretion performances place the alpha-amylase derived secretion system amongst the best heterologous secretion systems in Gram-negative bacteria reported so far. As for the quality of the secreted passenger proteins, data presented suggest that the system also allows the correct disulphide bond formation of chimera components, secreting a fully active passenger.