Structure and function of vacuolar Na+-translocating ATPase in Enterococcus hirae

J Bioenerg Biomembr. 1999 Feb;31(1):7-14. doi: 10.1023/a:1005499126939.


A Na+-translocating ATPase was discovered in a gram-positive bacterium Enterococcus hirae. Our biochemical and molecular biological studies revealed that this Na+-ATPase belongs to the vacuolar-type enzyme. Purified Na+-ATPase consisted of nine subunits: NtpA, B, C, D, E, F, G, I, and K; reconstituted proteoliposomes showed ATP-driven electrogenic Na+ translocation. All these subunits were encoded by the ntp operon: ntpFIKECGABDHJ. The deduced amino acid sequences of the major subunits, A, B, and K (16 kDa proteolipid), were highly similar to those of A, B, and proteolipid subunits of vacuolar ATPases, although the similarities of other subunits were moderate. The ntpJ gene encoded a K+ transporter independent of the Na+-ATPase. Expression of this operon, encoding two transport systems for Na+ and K+ ions, was regulated at transcriptional level by intracellular Na+ as the signal. Two related cation pumps, vacuolar Na+-ATPase and F0F1, H+-ATPase, coexist in this bacterium.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Catalysis
  • Cation Transport Proteins*
  • Enterococcus / enzymology*
  • Enterococcus / genetics
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Operon
  • Proton-Translocating ATPases / chemistry
  • Proton-Translocating ATPases / genetics
  • Proton-Translocating ATPases / metabolism*
  • Sodium-Hydrogen Exchangers / metabolism
  • Structure-Activity Relationship
  • Vacuolar Proton-Translocating ATPases*


  • Bacterial Proteins
  • Cation Transport Proteins
  • Membrane Proteins
  • Sodium-Hydrogen Exchangers
  • Adenosine Triphosphatases
  • NtpJ protein, bacteria
  • Vacuolar Proton-Translocating ATPases
  • sodium-translocating ATPase
  • Proton-Translocating ATPases