1ZCD

Crystal structure of the Na+/H+ antiporter NhaA

Summary for 1ZCD

• Entry DOI: 10.2210/pdb1zcd/pdb
• Descriptor: Na(+)/H(+) antiporter 1 (1 entity in total)
• Functional Keywords: antiporter, membrane protein
• Biological source: Escherichia coli
• Cellular location: Cell inner membrane; Multi-pass membrane protein: P13738
• Total number of polymer chains: 2
• Total formula weight: 82776.91

Authors

Hunte, C.,Screpanti, E.,Venturi, M.,Rimon, A.,Padan, E.,Michel, H. (deposition date: 2005-04-11, release date: 2005-07-05, Last modification date: 2024-03-13)

Primary citation

Hunte, C.,Screpanti, E.,Venturi, M.,Rimon, A.,Padan, E.,Michel, H.
Structure of a Na+/H+ antiporter and insights into mechanism of action and regulation by pH.
Nature, 435:1197-1202, 2005

PubMed Abstract: The control by Na+/H+ antiporters of sodium/proton concentration and cell volume is crucial for the viability of all cells. Adaptation to high salinity and/or extreme pH in plants and bacteria or in human heart muscles requires the action of Na+/H+ antiporters. Their activity is tightly controlled by pH. Here we present the crystal structure of pH-downregulated NhaA, the main antiporter of Escherichia coli and many enterobacteria. A negatively charged ion funnel opens to the cytoplasm and ends in the middle of the membrane at the putative ion-binding site. There, a unique assembly of two pairs of short helices connected by crossed, extended chains creates a balanced electrostatic environment. We propose that the binding of charged substrates causes an electric imbalance, inducing movements, that permit a rapid alternating-access mechanism. This ion-exchange machinery is regulated by a conformational change elicited by a pH signal perceived at the entry to the cytoplasmic funnel.

PubMed: 15988517
DOI: 10.1038/nature03692

Experimental method

X-RAY DIFFRACTION (3.45 Å)