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ExbB acts as a chaperone‐like protein to stabilize TonB in the cytoplasm
Author(s) -
Karlsson Margareta,
Hannavy Kevin,
Higgins Christopher F.
Publication year - 1993
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 - 10.1111/j.1365-2958.1993.tb01582.x
Subject(s) - biology , cytoplasm , chaperone (clinical) , microbiology and biotechnology , medicine , pathology
Summary The TonB protein is required to transduce energy from the cytoplasmic membrane to outer membrane transport proteins of Gram‐negative bacteria. Two accessory proteins, ExbB and ExbD, are required for TonB function and it has been suggested that TonB and ExbBD form a complex in the membrane. In this paper we demonstrate that there are two spatially distinct, functional interactions between ExbBD and TonB. First, there is an interaction between ExbBD and the N ‐terminal signal‐like peptide of TonB, probabiy the formation of a stable complex in the membrane. Second, ExbB interacts with TonB in the cytoplasm. This interaction involves the domain of TonB that is normally periplasmic. Thus, this is a transient interaction which occurs during the synthesis and/or localization of TonB, implying a chaperone‐like role for ExbB. The transmembrane topology of ExbB was shown to be consistent with this role.