Dataset Information

Functional analysis of the Na+,K+/H+ antiporter PeNHX3 from the tree halophyte Populus euphratica in yeast by model-guided mutagenesis.

ABSTRACT: Na+,K+/H+ antiporters are H+-coupled cotransporters that are crucial for cellular homeostasis. Populus euphratica, a well-known tree halophyte, contains six Na+/H+ antiporter genes (PeNHX1-6) that have been shown to function in salt tolerance. However, the catalytic mechanisms governing their ion transport remain largely unknown. Using the crystal structure of the Na+/H+ antiporter from the Escherichia coli (EcNhaA) as a template, we built the three-dimensional structure of PeNHX3 from P. euphratica. The PeNHX3 model displays the typical TM4-TM11 assembly that is critical for ion binding and translocation. The PeNHX3 structure follows the 'positive-inside' rule and exhibits a typical physicochemical property of the transporter proteins. Four conserved residues, including Tyr149, Asn187, Asp188, and Arg356, are indentified in the TM4-TM11 assembly region of PeNHX3. Mutagenesis analysis showed that these reserved residues were essential for the function of PeNHX3: Asn187 and Asp188 (forming a ND motif) controlled ion binding and translocation, and Tyr149 and Arg356 compensated helix dipoles in the TM4-TM11 assembly. PeNHX3 mediated Na+, K+ and Li+ transport in a yeast growth assay. Domain-switch analysis shows that TM11 is crucial to Li+ transport. The novel features of PeNHX3 in ion binding and translocation are discussed.

SUBMITTER: Wang L

PROVIDER: S-EPMC4122410 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Functional analysis of the Na+,K+/H+ antiporter PeNHX3 from the tree halophyte Populus euphratica in yeast by model-guided mutagenesis.

Wang Liguang L Feng Xueying X Zhao Hong H Wang Lidong L An Lizhe L Qiu Quan-Sheng QS

PloS one 20140805 8

Na+,K+/H+ antiporters are H+-coupled cotransporters that are crucial for cellular homeostasis. Populus euphratica, a well-known tree halophyte, contains six Na+/H+ antiporter genes (PeNHX1-6) that have been shown to function in salt tolerance. However, the catalytic mechanisms governing their ion transport remain largely unknown. Using the crystal structure of the Na+/H+ antiporter from the Escherichia coli (EcNhaA) as a template, we built the three-dimensional structure of PeNHX3 from P. euphra ...[more]

PMID: 25093858

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Dataset Information

Functional analysis of the Na+,K+/H+ antiporter PeNHX3 from the tree halophyte Populus euphratica in yeast by model-guided mutagenesis.

Publications

Functional analysis of the Na+,K+/H+ antiporter PeNHX3 from the tree halophyte Populus euphratica in yeast by model-guided mutagenesis.

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