A Small Periplasmic Protein with a Hydrophobic C-Terminal Residue Enhances DegP Proteolysis as a Suicide Activator

• DOI: 10.1128/jb.00519-17
• Publication Date: 2017-09-26T00:40:21Z
• Authors: Sungjae Kim; Inseok Song; Gaeul Eom; Seokhee Kim
• Keywords: Proteolysis; DsbA

DegP is a highly conserved protease that performs regulated proteolysis to selectively remove misfolded proteins in the periplasm of Escherichia coli Binding known be main mechanism activation, but it unknown whether any native can alter activity. Here, we show small periplasmic protein, YjfN, which upregulated by Cpx envelope stress response, functions as "suicide activator" for and promotes efficient degradation proteins. YjfN readily binds degraded DegP, hydrophobic C-terminal residue transient unfolding are critical. also activates trans while being accelerates denatured outer membrane OmpA, not easily recognized DegP. Although prevents OmpA aggregation, trans-activation effect mainly responsible degradation. Overexpression enhances viability cells protein induced presence less-active variant at high temperature. Collectively, suggest enhance relieving stresses may generate toxic proteins.IMPORTANCE Proper essential bacterial survival. This function performed protease, It binding activating protease. find substrate an activator first example showing ability directly The YjfN-mediated activation Our results novel under stress.