Computational study of the Na +/H + antiporter from Vibrio parahaemolyticus

Assaf Ganoth, Raphael Alhadeff, Isaiah T. Arkin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Sodium proton antiporters are ubiquitous membrane proteins that catalyze the exchange of Na + for protons throughout the biological world. The Escherichia coli NhaA is the archetypal Na +/H + antiporter and is absolutely essential for survival in high salt concentrations under alkaline conditions. Its crystal structure, accompanied by extensive molecular dynamics simulations, have provided an atomically detailed model of its mechanism. In this study, we utilized a combination of computational methodologies in order to construct a structural model for the Na +/H + antiporter from the gram-negative bacterium Vibrio parahaemolyticus. We explored its overall architecture by computational means and validated its stability and robustness. This protein belongs to a novel group of NhaA proteins that transports not only Na + and Li + as substrate ions, but K + as well, and was also found to miss a β-hairpin segment prevalent in other homologs of the Bacteria domain. We propose, for the first time, a structure of a prototype model of a β-hairpin-less NhaA that is selective to K +. Better understanding of the Vibrio parahaemolyticus NhaA structure-function may assist in studies on ion transport, pH regulation and designing selective blockers.

Original languageAmerican English
Pages (from-to)1877-1890
Number of pages14
JournalJournal of Molecular Modeling
Volume17
Issue number8
DOIs
StatePublished - Aug 2011

Bibliographical note

Funding Information:
This work was supported in part by grants from The Lady Davis Fellowship Trust and The Valazzi-Pikovsky Fellowship Fund (to A.G.), The Rudin Fellowship Trust (to R.A.) and the Israeli Science Foundation (784/01, 1249/05, 1581/08 to I.T.A.). I.T.A. is the Arthur Lejwa Professor of Structural Biochemistry at the Hebrew University of Jerusalem. The authors would like to thank Professor Aharon Oren from the Hebrew University of Jerusalem for fruitful discussions regarding bacterial phylogenetics.

Keywords

  • Antiporting
  • Membrane proteins

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