Probing the Structure and Function of the Cytosolic Domain of the Human Zinc Transporter ZnT8 with Nickel(II) Ions
Abstract
The human zinc transporter ZnT8 is needed for assembly of insulin hexamers for storage. Two common variants, one with tryptophan (W) and the other with arginine (R) at position 325, might be associated with a higher risk of developing type 2 diabetes.
Cytosolic domain of both variants of human ZnT8 were expressed. It was found that (i) the metal binding of the human protein is different from that of the bacterial proteins, (ii) the human protein has a C-terminal extension with three cysteine residues that bind a zinc(II) ion, and (iii) there are small differences in stability between the two variants.
In this investigation, we also employed nickel(II) ions as a probe for the spectroscopically silent Zn(II) ions and utilised colorimetric and fluorimetric indicators for Ni(II) ions to investigate metal binding. transporters.