Lacabanne D, Wiegand T, Di Cesare M, Orelle C, Ernst M, Jault JM, Meier BH, Böckmann A. Solid-State NMR Reveals Asymmetric ATP Hydrolysis in the Multidrug ABC Transporter BmrA.
J Am Chem Soc 2022;
144:12431-12442. [PMID:
35776907 PMCID:
PMC9284561 DOI:
10.1021/jacs.2c04287]
[Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
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The detailed mechanism
of ATP hydrolysis in ATP-binding cassette
(ABC) transporters is still not fully understood. Here, we employed 31P solid-state NMR to probe the conformational changes and
dynamics during the catalytic cycle by locking the multidrug ABC transporter
BmrA in prehydrolytic, transition, and posthydrolytic states, using
a combination of mutants and ATP analogues. The 31P spectra
reveal that ATP binds strongly in the prehydrolytic state to both
ATP-binding sites as inferred from the analysis of the nonhydrolytic
E504A mutant. In the transition state of wild-type BmrA, the symmetry
of the dimer is broken and only a single site is tightly bound to
ADP:Mg2+:vanadate, while the second site is more ‘open’
allowing exchange with the nucleotides in the solvent. In the posthydrolytic
state, weak binding, as characterized by chemical exchange with free
ADP and by asymmetric 31P–31P two-dimensional
(2D) correlation spectra, is observed for both sites. Revisiting the 13C spectra in light of these findings confirms the conformational
nonequivalence of the two nucleotide-binding sites in the transition
state. Our results show that following ATP binding, the symmetry of
the ATP-binding sites of BmrA is lost in the ATP-hydrolysis step,
but is then recovered in the posthydrolytic ADP-bound state.
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