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Accueil > Publications > Recherche par années > Années 2000 > 2001

Journet, L ; Bouveret, E ; Rigal, A ; Lloubes, R ; Lazdunski, C ; Benedetti, H

Import of colicins across the outer membrane of Escherichia coli involves multiple protein interactions in the periplasm

Molecular Microbiology 42 (2) 331-344

par Administrateur - publié le

Abstract :

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.