The rate of folding dictates substrate secretion by the Escherichia coli hemolysin type 1 secretion system.

ABSTRACT: Secretion of the Escherichia coli toxin hemolysin A (HlyA) is catalyzed by the membrane protein complex HlyB-HlyD-TolC and requires a secretion sequence located within the last 60 amino acids of HlyA. The Hly translocator complex exports a variety of passenger proteins when fused N-terminal to this secretion sequence. However, not all fusions are secreted efficiently. Here, we demonstrate that the maltose binding protein (MalE) lacking its natural export signal and fused to the HlyA secretion signal is poorly secreted by the Hly system. We anticipated that folding kinetics might be limiting secretion, and we therefore introduced the "folding" mutation Y283D. Indeed this mutant fusion protein was secreted at a much higher level. This level was further enhanced by the introduction of a secon

SUBMITTER: Bakkes PJ 

PROVIDER: S-EPMC3003356 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature