Structure-function activity of the human sodium-dependent multivitamin transporter: role of His¹¹⁵ and His²⁵⁴.

ABSTRACT: Intestinal absorption of biotin occurs via a Na(+)-dependent carrier-mediated process that involves the sodium-dependent multivitamin transporter (SMVT; product of the Slc5a6 gene). The SMVT system is exclusively expressed at the apical membrane domain of the polarized intestinal epithelial cells. Whereas previous studies from our laboratory and others have characterized different physiological and biological aspects of SMVT, little is currently known about its structure-function activity relationship. Using site-directed mutagenesis approach, we examined the role of the positively charged histidine (His) residues of the human SMVT (hSMVT) in transporting the negatively charged biotin. Of the seven conserved (across species) His residues in the hSMVT polypeptide, only His¹¹⁵ and His²⁵⁴ wer

SUBMITTER: Ghosal A 

PROVIDER: S-EPMC3023183 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature