4DX6

Transport of drugs by the multidrug transporter AcrB involves an access and a deep binding pocket that are separated by a switch-loop

4DX6 の概要

• エントリーDOI: 10.2210/pdb4dx6/pdb
• 関連するPDBエントリー: 4DX5 4DX7
• 分子名称: Acriflavine resistance protein B, DARPIN, DODECYL-BETA-D-MALTOSIDE (3 entities in total)
• 機能のキーワード: darpin, multidrug efflux protein, membrane protein, transport protein
• 由来する生物種: Escherichia coli; 詳細
• 細胞内の位置: Cell inner membrane; Multi-pass membrane protein: P31224
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 384589.44

構造登録者

Eicher, T.,Cha, H.,Seeger, M.A.,Brandstaetter, L.,El-Delik, J.,Bohnert, J.A.,Kern, W.V.,Verrey, F.,Gruetter, M.G.,Diederichs, K.,Pos, K.M. (登録日: 2012-02-27, 公開日: 2012-05-02, 最終更新日: 2024-02-28)

主引用文献

Eicher, T.,Cha, H.J.,Seeger, M.A.,Brandstatter, L.,El-Delik, J.,Bohnert, J.A.,Kern, W.V.,Verrey, F.,Grutter, M.G.,Diederichs, K.,Pos, K.M.
Transport of drugs by the multidrug transporter AcrB involves an access and a deep binding pocket that are separated by a switch-loop.
Proc.Natl.Acad.Sci.USA, 109:5687-5692, 2012

PubMed Abstract: AcrAB-TolC is the major efflux protein complex in Escherichia coli extruding a vast variety of antimicrobial agents from the cell. The inner membrane component AcrB is a homotrimer, and it has been postulated that the monomers cycle consecutively through three conformational stages designated loose (L), tight (T), and open (O) in a concerted fashion. Binding of drugs has been shown at a periplasmic deep binding pocket in the T conformation. The initial drug-binding step and transport toward this drug-binding site has been elusive thus far. Here we report high resolution structures (1.9-2.25 Å) of AcrB/designed ankyrin repeat protein (DARPin) complexes with bound minocycline or doxorubicin. In the AcrB/doxorubicin cocrystal structure, binding of three doxorubicin molecules is apparent, with one doxorubicin molecule bound in the deep binding pocket of the T monomer and two doxorubicin molecules in a stacked sandwich arrangement in an access pocket at the lateral periplasmic cleft of the L monomer. This access pocket is separated from the deep binding pocket apparent in the T monomer by a switch-loop. The localization and conformational flexibility of this loop seems to be important for large substrates, because a G616N AcrB variant deficient in macrolide transport exhibits an altered conformation within this loop region. Transport seems to be a stepwise process of initial drug uptake in the access pocket of the L monomer and subsequent accommodation of the drug in the deep binding pocket during the L to T transition to the internal deep binding pocket of the T monomer.

PubMed: 22451937
DOI: 10.1073/pnas.1114944109

実験手法

X-RAY DIFFRACTION (2.9 Å)