Steps Towards Understanding the Role Of DegP in Secretion of the Bordetella pertussis Autotransporter Protein BrkA

Abstract

BrkA is a type V secretion system found in Bordetella pertussis, the causative agent of whooping cough. Research has shown that the β-barrel formed by autotransporters is too small to allow for the translocation of the passenger domain by itself. However, periplasmic chaperones such as DegP, SurA, and Skp, can interact with certain autotransporters to keep them in a translocation-competent unfolded state prior to translocation across the outer membrane. DegP, a temperature-dependent chaperone and protease, is found in the periplasm of Gram-negative bacteria. It is unclear how DegP interacts with BrkA in the process of its translocation across the outer membrane. In this study, we validated whether degP was knocked out in the JW0157 Escherichia coli strain, performed site-directed mutagenesis to insert 6 histidine residues into the brkA plasmid, and conducted Western blot to determine the effect of DegP in BrkA secretion. The degP knockout strain was successfully validated, but the site-directed mutagenesis process and Western blots were unsuccessful. Further Western blot attempts are necessary in order to address the aim presented.