Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.

Gram-negative bacteria such as E. coli use tripartite efflux pumps such as AcrAB-TolC to expel antibiotics and noxious compounds. A key feature of the inner membrane transporter component, AcrB, is a short stretch of residues known as the gate/switch loop that divides the proximal and distal substra...

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Main Authors: Abdessamad Ababou, Vassilis Koronakis
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2016-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0159154&type=printable
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author Abdessamad Ababou
Vassilis Koronakis
author_facet Abdessamad Ababou
Vassilis Koronakis
author_sort Abdessamad Ababou
collection DOAJ
description Gram-negative bacteria such as E. coli use tripartite efflux pumps such as AcrAB-TolC to expel antibiotics and noxious compounds. A key feature of the inner membrane transporter component, AcrB, is a short stretch of residues known as the gate/switch loop that divides the proximal and distal substrate binding pockets. Amino acid substitutions of the gate loop are known to decrease antibiotic resistance conferred by AcrB. Here we present two new AcrB gate loop variants, the first stripped of its bulky side chains, and a second in which the gate loop is removed entirely. By determining the crystal structures of the variant AcrB proteins in the presence and absence of erythromycin and assessing their ability to confer erythromycin tolerance, we demonstrate that the gate loop is important for AcrB export activity but is not required for erythromycin binding.
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publisher Public Library of Science (PLoS)
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series PLoS ONE
spelling doaj-art-915372957cbb4f7bbd40ff2c70673f142025-08-20T03:26:21ZengPublic Library of Science (PLoS)PLoS ONE1932-62032016-01-01117e015915410.1371/journal.pone.0159154Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.Abdessamad AbabouVassilis KoronakisGram-negative bacteria such as E. coli use tripartite efflux pumps such as AcrAB-TolC to expel antibiotics and noxious compounds. A key feature of the inner membrane transporter component, AcrB, is a short stretch of residues known as the gate/switch loop that divides the proximal and distal substrate binding pockets. Amino acid substitutions of the gate loop are known to decrease antibiotic resistance conferred by AcrB. Here we present two new AcrB gate loop variants, the first stripped of its bulky side chains, and a second in which the gate loop is removed entirely. By determining the crystal structures of the variant AcrB proteins in the presence and absence of erythromycin and assessing their ability to confer erythromycin tolerance, we demonstrate that the gate loop is important for AcrB export activity but is not required for erythromycin binding.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0159154&type=printable
spellingShingle Abdessamad Ababou
Vassilis Koronakis
Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.
PLoS ONE
title Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.
title_full Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.
title_fullStr Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.
title_full_unstemmed Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.
title_short Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate.
title_sort structures of gate loop variants of the acrb drug efflux pump bound by erythromycin substrate
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0159154&type=printable
work_keys_str_mv AT abdessamadababou structuresofgateloopvariantsoftheacrbdrugeffluxpumpboundbyerythromycinsubstrate
AT vassiliskoronakis structuresofgateloopvariantsoftheacrbdrugeffluxpumpboundbyerythromycinsubstrate