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Import of colicins across the outer membrane of Escherichia coli involves multiple protein interactions in the periplasm
Author(s) -
Journet Laure,
Bouveret Emmanuelle,
Rigal Alain,
Lloubes Roland,
Lazdunski Claude,
Bénédetti Hélène
Publication year - 2001
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2001.02592.x
Subject(s) - colicin , periplasmic space , bacterial outer membrane , biology , escherichia coli , chromosomal translocation , transmembrane protein , inner membrane , microbiology and biotechnology , transmembrane domain , genetics , membrane , gene , receptor
Several proteins of the Tol/Pal system are required for group A colicin import into Escherichia coli . Colicin A interacts with TolA and TolB via distinct regions of its N‐terminal domain. Both interactions are required for colicin translocation. Using in vivo and in vitro approaches, we show in this study that colicin A also interacts with a third component of the Tol/Pal system required for colicin import, TolR. This interaction is specific to colicins dependent on TolR for their translocation, strongly suggesting a direct involvement of the interaction in the colicin translocation step. TolR is anchored to the inner membrane by a single transmembrane segment and protrudes into the periplasm. The interaction involves part of the periplasmic domain of TolR and a small region of the colicin A N‐terminal domain. This region and the other regions responsible for the interaction with TolA and TolB have been mapped precisely within the colicin A N‐terminal domain and appear to be arranged linearly in the colicin sequence. Multiple contacts with periplasmic‐exposed Tol proteins are therefore a general principle required for group A colicin translocation.