Respiration system FNR protein effect on type Ⅲ secretion system in E.coli O157 ∶ H7 / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the effect of FNR on type Ⅲ secretion system (T3SS) in E.coli O157 ∶ H7.Methods fnr mutant was constructed by λRed recombineering technology promoted by Bet and Exo proteins using PCR products.Results Through bacterial infection assays and immunofluorescence microscopy,it was found that the adhesion ability was decreased insignificantly infnr mutant compared to the wild type ZAP198.However,the secreted proteins were reduced significantly in the mutant from the secretion profile.Conclusion The reason might be that high ClpXP protein caused by the deletion of fnr degraded GrlA resulting in the inhibition of LEE(locus of enterocyte effacement) and T3SS.