The first external loop of the metal ion transporter DCT1 is involved in metal ion binding and specificity.

ABSTRACT: The yeast null mutant smf1Delta cannot grow on medium containing EGTA. Expression of Smf1p or the mammalian transporter DCT1 (Slc11a2) suppresses the above-mentioned phenotype. Both can also be expressed in Xenopus oocytes, and the uptake activity and their electrophysiological properties can be studied. We used these systems to analyze the properties of mutations in the predicted external loop I of DCT1. The sensitivity of the transporter to amino acid substitutions in this region is manifested by the mutation G119A, which resulted in almost complete inhibition of the metal ion uptake activity and marked changes in the pre-steady-state currents in Xenopus oocytes. The mutation Q126D abolished the uptake and the electrophysiology, but the double mutant D124A/Q126D partially restored it and

SUBMITTER: Cohen A 

PROVIDER: S-EPMC196866 | biostudies-literature | 2003 Sep

REPOSITORIES: biostudies-literature