Preliminary Study On Genetic Modification Of E.coli And Thurmulus Tat System's Species-Specific Genes

Protein Tat (twin-arginine translocation pathway) transport system differs from the widespread Sec (Sec-dependent protein translocation pathway)- transport system, but has similarities with the ApH pathway which exists in green plants. The core and conserve part of the signal peptide is S/ T- R - R- x- F- L- K. TatA, TatB, TatC and TatE are the four kinds of proteins of the E. coli Tat system. Tat system mostly transport proteins related with breath-chain.E.coli Tat mutants are found to be sensitive to SDS (sodium dodecysulphate) , and could not grow on minimal TMAO (trimethyl amine N-oxide).Tat system has the species specificity; different species do not have the same functions. Thurmulus has two copies of tatC genes and one copy of tatA gene. Thurmulus tatAC and tatC genes were cloned into the plasmid pET22, and plasmids p8773 and p8774 were constructed. Then the plasmids were transfered into the E.coli Tat mutants, and the SDS sensitive concentrations of the trans-mutants were determined. By using SDSand TMAO,it was found that Thurmulus'tat genes cannot complement E.coli Tat mutants.NG was also used to get the E.coli and Thurmulus complement strains by SDS but failed. The results indicated that it is quite difficult to make any genetic modification on E.coli and Thurmulus Tat system's species specific genes.