title: R76 in transmembrane domain 3 of the aspartate:alanine transporter AspT is involved in substrate transport.
abstract: The L-aspartate:L-alanine antiporter of Tetragenococcus halophilus (AspT) possesses an arginine residue (R76) within the GxxxG motif in the central part of transmembrane domain 3 (TM3)-a residue that has been estimated to transport function. In this study, we carried out amino acid substitutions of R76 and used proteoliposome reconstitution for analyzing the transport function of each substitution. Both l-aspartate and l-alanine transport assays showed that R76K has higher activity than the AspT-WT (R76), whereas R76D and R76E have lower activity than the AspT-WT. These results suggest that R76 is involved in AspT substrate transport.
authors: a Department of Microbial Biotechnology , Graduate School of Agricultural Science, Tohoku University , Sendai , Japan.
authors: Satomi
authors: S
authors: Suzuki
authors: a Department of Microbial Biotechnology , Graduate School of Agricultural Science, Tohoku University , Sendai , Japan.
authors: Kei
authors: K
authors: Nanatani
authors: a Department of Microbial Biotechnology , Graduate School of Agricultural Science, Tohoku University , Sendai , Japan.
authors: Keietsu
authors: K
authors: Abe
mesh_terms: D000409:Alanine / Q000378:metabolism*; D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D026901:Membrane Transport Proteins; D001224:Aspartic Acid; D000409:Alanine
keywords: GxxxG; amino acid transporter; liposome; substrate transport; transport activity