SLC6 proteins (also called the sodium- and chloride-dependent neurotransmitter transporter family or Na+/Cl--dependent transporter family) include neurotransmitter transporters (NTTs): these are sodium- and chloride-dependent plasma membrane transporters for the monoamine neurotransmitters serotonin (5-hydroxytryptamine), dopamine, and norepinephrine, and the amino acid neurotransmitters GABA and glycine. These NTTs are widely expressed in the mammalian brain, involved in regulating neurotransmitter signaling and homeostasis, and the target of a range of therapeutic drugs for the treatment of psychiatric diseases. Bacterial members of the SLC6 family include the LeuT amino acid transporter. An arrangement of 12 transmembrane (TM) helices appears to be as a common topological motif for eukaryotic and some prokaryotic and archaeal NTTs. However, this subfamily which contains the majority of bacterial members and some archaeal members, appears to contain only 11 TMs; for example the functional Fusobacterium nucleatum tyrosine transporter Tyt1.
Comment:based on Aquifex aeolicus LeuT (SLC6) with structure
Comment:One of two Na+ binding sites in Aquifex aeolicus LeuT. It binds the Na+ ion designated Na2, and appears conserved in Vibrio parahaemolyticus vSGLT and other SLC5 proteins
Jiyao W et al.(2023). "The conserved domain database in 2023.",