Quantification of known components of the Escherichia coli TonB energy transduction system: TonB, ExbB, ExbD and FepA
نویسندگان
چکیده
منابع مشابه
ExbB and ExbD do not function independently in TonB-dependent energy transduction.
ExbB and ExbD proteins are part of the TonB-dependent energy transduction system and are encoded by the exb operon in Escherichia coli. TonB, the energy transducer, appears to go through a cycle during energy transduction, with the absence of both ExbB and ExbD creating blocks at two points: (i) in the inability of TonB to respond to the cytoplasmic membrane proton motive force and (ii) in the ...
متن کاملConfined Mobility of TonB and FepA in Escherichia coli Membranes
The important process of nutrient uptake in Escherichia coli, in many cases, involves transit of the nutrient through a class of beta-barrel proteins in the outer membrane known as TonB-dependent transporters (TBDTs) and requires interaction with the inner membrane protein TonB. Here we have imaged the mobility of the ferric enterobactin transporter FepA and TonB by tracking them in the membran...
متن کاملCharacterization of the exbBD operon of Escherichia coli and the role of ExbB and ExbD in TonB function and stability.
TonB protein appears to couple the electrochemical potential of the cytoplasmic membrane to active transport across the essentially unenergized outer membrane of gram-negative bacteria. ExbB protein has been identified as an auxiliary protein in this process. In this paper we show that ExbD protein, encoded by an adjacent gene in the exb cluster at 65', was also required for TonB-dependent ener...
متن کاملThe ExbD periplasmic domain contains distinct functional regions for two stages in TonB energization.
The TonB system of gram-negative bacteria energizes the active transport of diverse nutrients through high-affinity TonB-gated outer membrane transporters using energy derived from the cytoplasmic membrane proton motive force. Cytoplasmic membrane proteins ExbB and ExbD harness the proton gradient to energize TonB, which directly contacts and transmits this energy to ligand-loaded transporters....
متن کاملThe same periplasmic ExbD residues mediate in vivo interactions between ExbD homodimers and ExbD-TonB heterodimers.
The TonB system couples cytoplasmic membrane proton motive force to TonB-gated outer membrane transporters for active transport of nutrients into the periplasm. In Escherichia coli, cytoplasmic membrane proteins ExbB and ExbD promote conformational changes in TonB, which transmits this energy to the transporters. The only known energy-dependent interaction occurs between the periplasmic domains...
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ژورنال
عنوان ژورنال: Molecular Microbiology
سال: 2002
ISSN: 0950-382X,1365-2958
DOI: 10.1046/j.1365-2958.2002.02880.x