TY - JOUR
T1 - Protonation of a glutamate residue modulates the dynamics of the drug transporter EmrE
AU - Gayen, Anindita
AU - Leninger, Maureen
AU - Traaseth, Nathaniel J.
N1 - Funding Information:
This work was supported by US National Institutes of Health (NIH) grant R01AI108889 and start-up funds from New York University (NYU) to N.J.T. M.L. acknowledges support from a Margaret Strauss Kramer Fellowship. The NMR data collected with a cryoprobe at NYU was supported by an NIH S10 grant (OD016343). Data collected at the New York Structural Biology Center was made possible by a grant from NYSTAR. The authors thank R. Turner at the University of Calgary for providing wild-type EmrE in the pMS119EH vector, M.-K. Cho for assistance of the initial NMR experiments, A. Sae Her for assistance in protein purification, and D. Buccella at NYU for use of the spectrofluorometer.
Funding Information:
This work was supported by US National Institutes of Health (NIH) grant R01AI108889 and start-up funds from New York University (NYU) to N.J.T. M.L. acknowledges support from a Margaret Strauss Kramer Fellowship. The NMR data collected with a cryoprobe at NYU was supported by an NIH S10 grant (OD016343). Data collected at the New York Structural Biology Center was made possible by a grant from NYSTAR.
Publisher Copyright:
© 2016 Nature America, Inc. All rights reserved.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Secondary active transport proteins play a central role in conferring bacterial multidrug resistance. In this work, we investigated the proton-coupled transport mechanism for the Escherichia coli drug efflux pump EmrE using NMR spectroscopy. Our results show that the global conformational motions necessary for transport are modulated in an allosteric fashion by the protonation state of a membrane-embedded glutamate residue. These observations directly correlate with the resistance phenotype for wild-type EmrE and the E14D mutant as a function of pH. Furthermore, our results support a model in which the pH gradient across the inner membrane of E. coli may be used on a mechanistic level to shift the equilibrium of the transporter in favor of an inward-open resting conformation poised for drug binding.
AB - Secondary active transport proteins play a central role in conferring bacterial multidrug resistance. In this work, we investigated the proton-coupled transport mechanism for the Escherichia coli drug efflux pump EmrE using NMR spectroscopy. Our results show that the global conformational motions necessary for transport are modulated in an allosteric fashion by the protonation state of a membrane-embedded glutamate residue. These observations directly correlate with the resistance phenotype for wild-type EmrE and the E14D mutant as a function of pH. Furthermore, our results support a model in which the pH gradient across the inner membrane of E. coli may be used on a mechanistic level to shift the equilibrium of the transporter in favor of an inward-open resting conformation poised for drug binding.
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U2 - 10.1038/nchembio.1999
DO - 10.1038/nchembio.1999
M3 - Article
C2 - 26751516
AN - SCOPUS:84954466066
VL - 12
SP - 141
EP - 145
JO - Nature Chemical Biology
JF - Nature Chemical Biology
SN - 1552-4450
IS - 3
ER -