Stepwise folding of an autotransporter passenger domain is not essential for its secretion

Abstract

Background: It has been proposed that stepwise folding of the extracellular (passenger) domains of bacterial autotransporter proteins drives their secretion. Results: Mutations in N-terminal or medial segments of a passenger domain that severely impair folding only moderately reduce secretion efficiency. Conclusion: Stepwise folding only partially accounts for the energetics of autotransporter secretion. Significance: Autotransporter secretion may involve the use of a novel energy source. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.