TY  - JOUR
A1  - Alkoby, Dudu
A1  - Rimon, Abraham
A1  - Burdak, Maral
A1  - Patiño-Ruiz, Miyer Fabián
A1  - Călinescu, Octavian
A1  - Fendler, Klaus
A1  - Padan, Etana
T1  - NhaA Na+/H+ antiporter mutants that hardly react to the membrane potential
T2  - PLoS One
N2  - pH and Na+ homeostasis in all cells requires Na+/H+ antiporters. The crystal structure, obtained at pH 4, of NhaA, the main antiporter of Escherichia coli, has provided general insights into an antiporter mechanism and its unique pH regulation. Here, we describe a general method to select various NhaA mutants from a library of randomly mutagenized NhaA. The selected mutants, A167P and F267C are described in detail. Both mutants are expressed in Escherichia coli EP432 cells at 70–95% of the wild type but grow on selective medium only at neutral pH, A167P on Li+ (0.1 M) and F267C on Na+ (0.6 M). Surprising for an electrogenic secondary transporter, and opposed to wild type NhaA, the rates of A167P and F267C are almost indifferent to membrane potential. Detailed kinetic analysis reveals that in both mutants the rate limiting step of the cation exchange cycle is changed from an electrogenic to an electroneutral reaction.
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/33453
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-334535
SN  - 1932-6203
N1  - Copyright: © 2014 Alkoby et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
VL  - 9
IS  - (4):e93200
PB  - PLoS
CY  - Lawrence, Kan.
ER  -