Membrane topology of the electrogenic aspartate-alanine antiporter AspT of Tetragenococcus halophilus

Kei Nanatani, Fumito Ohonishi, Hiroshi Yoneyama, Tasuku Nakajima, Keietsu Abe

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


AspT is an electrogenic aspartate:alanine exchange protein that represents the vectorial component of a proton-motive metabolic cycle found in some strains of Tetragenococcus halophilus. AspT is the sole member of a new family, the Aspartate: Alanine Exchanger (AAE) family, in secondary transporters, according to the computational classification proposed by Saier et al. ( We analyzed the topology of AspT biochemically, by using fusion methods in combination with alkaline phosphatase or β-lactamase. These results suggested that AspT has a unique topology; 8 TMS, a large cytoplasmic loop (183 amino acids) between TMS5 and TMS6, and N- and C-termini that both face the periplasm. These results demonstrated a unique 2D-structure of AspT as the novel AAE family.

Original languageEnglish
Pages (from-to)20-26
Number of pages7
JournalBiochemical and biophysical research communications
Issue number1
Publication statusPublished - 2005 Mar 4


  • Aspartate:Alanine Antiporter
  • Electrogenic
  • Fusion methods
  • Membrane topology
  • Proton-motive force

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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