Structural insights into chaperone addiction of toxin-antitoxin systems

摘要: SecB chaperones assist protein export by binding both unfolded proteins and the SecA motor. Certain homologs can also control toxin-antitoxin (TA) systems known to modulate bacterial growth in response stress. In such TA-chaperone (TAC) systems, assists folding prevents degradation of antitoxin, thus facilitating toxin inhibition. Chaperone dependency is conferred a C-terminal extension antitoxin as chaperone addiction (ChAD) sequence, which makes aggregation-prone Using TAC Mycobacterium tuberculosis, we present structure SecB-like bound its ChAD peptide. We find differences interfaces when compared SecB–SecA or SecB-preprotein complexes, show that reach functional form while chaperone. This work reveals how use discrete surface regions accommodate different clients partners thereby expand their substrate repertoire functions. be associated with stress-responsive type II toxin–antitoxin tripartite toxin-antitoxin-chaperone (TAC). Here authors provide structural insights into TACs presenting crystal M. tuberculosis TA-associated complex (chaperone addiction) HigA1.