Membrane topology of the electrogenic aspartate-alanine antiporter AspT of Tetragenococcus halophilus.
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. (http://www.biology.ucsd.edu/~msaier/transport/). We analyzed the topology of AspT biochemically, by using fusion methods in combination with alkaline phosphatase or beta-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.
Nanatani
Kei
K
Laboratory of Enzymology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
Ohonishi
Fumito
F
Yoneyama
Hiroshi
H
Nakajima
Tasuku
T
Abe
Keietsu
K
D000595:Amino Acid Sequence; D017920:Antiporters / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism*; D016983:Enterococcus / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship
D017920:Antiporters; D011993:Recombinant Fusion Proteins