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11  structures 6387  species 1  interaction 7366  sequences 12  architectures

Family: Na_H_antiport_1 (PF06965)

Summary: Na+/H+ antiporter 1

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This is the Wikipedia entry entitled "Sodium/proton antiporter 1". More...

Sodium/proton antiporter 1 Edit Wikipedia article

Na+/H+ antiporter 1
1zcd opm.png
Symbol Na_H_antiport_1
Pfam PF06965
InterPro IPR004670
TCDB 2.A.36
OPM superfamily 346
OPM protein 1zcd

Na+/H+ antiporter 1 family contains a number of bacterial sodium-proton antiporter (SPAP) 1 proteins. These are integral membrane proteins that catalyse the exchange of H+ for Na+ in a manner that is highly dependent on the pH.

In particular, the Escherichia coli NhaA Na+:H+ Antiporter (NhaA) protein probably functions in the regulation of the internal pH when the external pH is alkaline.[1] It also uses the H+ gradient to expel Na+ from the cell. Its activity is highly pH dependent.

A model[2] of the Last Universal Common Ancestor (LUCA) of all life on Earth suggests a SPAP was crucial for extracting energy from the natural proton gradients across the surface of underwater hydrothermal vents. A SPAP could have increased by 60% the free energy obtainable from proton gradients through a hypothesized leaky proto-membrane of LUCA; and a SPAP would have increasingly assisted proton pump efficiency in the less permeable membranes of LUCA's descendants, Archaea and Bacteria.


This article incorporates text from the public domain Pfam and InterPro IPR004670

  1. ^ Karpel, R.; Alon, T.; Glaser, G.; Schuldiner, S.; Padan, E. (1991). "Expression of a sodium proton antiporter (NhaA) in Escherichia coli is induced by Na+ and Li+ ions". The Journal of biological chemistry 266 (32): 21753–21759. PMID 1657980. 
  2. ^ Sojo, Victor; Porniankowski, Andrew; Lane, Nick (August 12, 2014). "A Bioenergetic Basis for Membrane Divergence in Archaea and Bacteria". PLOS Biology 12 (8). doi:10.1371/journal.pbio.1001926. Retrieved 18 August 2014. 

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This family contains a number of bacterial Na+/H+ antiporter 1 proteins. These are integral membrane proteins that catalyse the exchange of H+ for Na+ in a manner that is highly dependent on the pH [1].

Literature references

  1. Karpel R, Alon T, Glaser G, Schuldiner S, Padan E; , J Biol Chem 1991;266:21753-21759.: Expression of a sodium proton antiporter (NhaA) in Escherichia coli is induced by Na+ and Li+ ions. PUBMED:1657980 EPMC:1657980

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR004670

NhaA is a sodium ion/proton antiporter that uses the proton electrochemical gradient to expel sodium ions from the cytoplasm and functions primarily in the adaptation to high salinity at alkaline pH. NhaA is also believed to be responsible for adaptation to alkaline pH when sodium is available. NhaA is one of the three known sodium ion/proton antiporters in Escherichia coli along with NhaB and ChaA, though there are other mechanisms for Na+ extrusion such as NDH-I complicating the determination of the precise roles of each of the transporters [PUBMED:19448069].

Gene Ontology

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Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan CPA_AT (CL0064), which has the following description:

This Clan contains transporter proteins that belong to the CPA superfamily and AT superfamily according to TCDB [1].

The clan contains the following 13 members:

Asp-Al_Ex Cons_hypoth698 DUF340 DUF819 Glt_symporter KdgT Mem_trans Na_H_antiport_1 Na_H_Exchanger OAD_beta SBF SBF_like Sbt_1


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Seed source: Pfam-B_1828 (release 10.0)
Previous IDs: none
Type: Family
Author: Vella Briffa B
Number in seed: 425
Number in full: 7366
Average length of the domain: 367.20 aa
Average identity of full alignment: 54 %
Average coverage of the sequence by the domain: 91.67 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 22.2 22.2
Trusted cut-off 22.6 22.4
Noise cut-off 21.3 22.1
Model length: 376
Family (HMM) version: 8
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Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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There is 1 interaction for this family. More...



For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Na_H_antiport_1 domain has been found. There are 11 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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