Amino acid transporters molecular cloning

Prior to its cloning, GLT-1 was reconstituted and purihed and shown to have a relative molecular mass of 64 kDa, which agrees well both with the value of 65 kDa of the purihed and deglycosylated transporter (28,37) and its 573 amino acids determined from its nucleotide sequence (25). Reconstituted GLT-1 has been shown to form dimers, trimers, and higher molecular-weight homomers in the absence of reducing agents (38). The possibility of homomeric assemblies is corroborated by a recent freeze fracture, which shows pentameric assemblies (39). 

The cloned 5-HT transporter from rat basophilic leukemia cells by Hofiinan et al. [1] consists of 653 amino acids and has a relative molecular mass of about 73 kD whereas the 5-HT tremsporter from rat midbrain and brainstem cloned by Blakely et al. [2] consists of 607 amino acids and has a relative molecular mass of 68 kD. 

Lesch et al. [3] reported the cloning and sequence analysis of a c-DNA encoding a 5-HT transporter from humeui dorsal raphe nuclei consisting of630 amino acids and having a relative molecular mass of about 70 kD. 

---