Open AccessSecretion of the Escherichia coli K‐12 SheA hemolysin is independent of its cytolytic activity
Author(s) -
Castillo Francisco J,
Moreno Felipe,
Castillo Ignacio
Publication year - 2001
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2001.tb10898.x
Subject(s) - periplasmic space , secretion , hemolysin , escherichia coli , cytolysis , extracellular , biology , microbiology and biotechnology , mutant , biochemistry , virulence , gene , cytotoxicity , in vitro
The Escherichia coli K‐12 sheA gene encodes a pore‐forming hemolysin that is secreted to the medium by a hitherto unidentified mechanism. To study SheA secretion, we constructed fusions between SheA and the mature form of the periplasmic enzyme β‐lactamase, and performed site‐directed mutagenesis on these constructs. The SheA‐Bla and Bla‐SheA hybrid proteins displayed hemolytic activity and were efficiently exported to the extracellular medium. Our results with mutant hybrid proteins show that secretion of SheA is independent of its cytolytic activity, that secretion is paralleled by a transient leakage of periplasmic contents to the extracellular medium, and that deletion of the 11 C‐terminal residues of SheA has no effect on its secretion and cytolytic activity.