Dynamics of a bacterial multidrug ABC transporter in the inward- and outward-facing conformations

Shahid Mehmood, Carmen Domene Nunez, Eric Forest, Jean-Michel Jault

Research output: Contribution to journalArticlepeer-review

71 Citations (Scopus)

Abstract

The study of membrane proteins remains a challenging task, and approaches to unravel their dynamics are scarce. Here, we applied hydrogen/deuterium exchange (HDX) coupled to mass spectrometry to probe the motions of a bacterial multidrug ATP-binding cassette (ABC) transporter, BmrA, in the inward-facing (resting state) and outward-facing (ATP-bound) conformations. Trypsin digestion and global or local HDX support the transition between inward- and outward-facing conformations during the catalytic cycle of BmrA. However, in the resting state, peptides from the two intracellular domains, especially ICD2, show a much faster HDX than in the closed state. This shows that these two subdomains are very flexible in this conformation. Additionally, molecular dynamics simulations suggest a large fluctuation of the Cα positions from ICD2 residues in the inward-facing conformation of a related transporter, MsbA. These results highlight the unexpected flexibility of ABC exporters in the resting state and underline the power of HDX coupled to mass spectrometry to explore conformational changes and dynamics of large membrane proteins.
Original languageEnglish
Pages (from-to)10832-10836
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number27
DOIs
Publication statusPublished - 3 Jul 2012

Keywords

  • ATPase cycle, BACILLUS-SUBTILIS, MOLECULAR-BASIS, structural biology, BINDING CASSETTE TRANSPORTER, ATP-BINDING, P-GLYCOPROTEINS, CRYSTAL-STRUCTURE, ALTERNATING ACCESS, detergent, HYDROGEN-EXCHANGE, BMRA, MASS-SPECTROMETRY

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