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Tripartite transporters as mechanotransmitters in periplasmic alternating‐access mechanisms
Author(s) -
Murakami Satoshi,
Okada Ui,
Veen Hendrik W.
Publication year - 2020
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13929
Subject(s) - periplasmic space , atp hydrolysis , transmembrane protein , biochemistry , biophysics , bacterial outer membrane , membrane transport protein , conformational change , transporter , atp binding cassette transporter , transport protein , transmembrane domain , inner membrane , chemistry , cyclic nucleotide binding domain , microbiology and biotechnology , biology , atpase , membrane , nucleotide , escherichia coli , enzyme , gene , receptor
To remove xenobiotics from the periplasmic space, Gram‐negative bacteria utilise unique tripartite efflux systems in which a molecular engine in the plasma membrane connects to periplasmic and outer membrane subunits. Substrates bind to periplasmic sections of the engine or sometimes to the periplasmic subunits. Then, the tripartite machines undergo conformational changes that allow the movement of the substrates down the substrate translocation pathway to the outside of the cell. The transmembrane (TM) domains of the tripartite resistance‐nodulation‐drug‐resistance (RND) transporters drive these conformational changes by converting proton motive force into mechanical motion. Similarly, the TM domains of tripartite ATP‐binding cassette (ABC) transporters transmit mechanical movement associated with nucleotide binding and hydrolysis at the nucleotide‐binding domains to the relevant subunits in the periplasm. In this way, metabolic energy is coupled to periplasmic alternating‐access mechanisms to achieve substrate transport across the outer membrane.