Structural modeling and electron paramagnetic resonance spectroscopy of the human Na+/H+ exchanger isoform 1, NHE1.

ABSTRACT: We previously presented evidence that transmembrane domain (TM) IV and TM X-XI are important for inhibitor binding and ion transport by the human Na(+)/H(+) exchanger, hNHE1 (Pedersen, S. F., King, S. A., Nygaard, E. B., Rigor, R. R., and Cala, P. M. (2007) J. Biol. Chem. 282, 19716-19727). Here, we present a structural model of the transmembrane part of hNHE1 that further supports this conclusion. The hNHE1 model was based on the crystal structure of the Escherichia coli Na(+)/H(+) antiporter, NhaA, and previous cysteine scanning accessibility studies of hNHE1 and was validated by EPR spectroscopy of spin labels in TM IV and TM XI, as well as by functional analysis of hNHE1 mutants. Removal of all endogenous cysteines in hNHE1, introduction of the mutations A173C (TM IV) and/or I461C (TM

SUBMITTER: Nygaard EB 

PROVIDER: S-EPMC3013023 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature