| The human Anion Exchanger, AE1, facilitates the electroneutral exchange of chloride for bicarbonate across the erythrocyte membrane. AE1, which comprises 50% of the erythrocyte integral membrane protein, plays a central role in CO2 metabolism and pH regulation. The 55 kDa membrane domain of AE1 (AE1MD) has 12-14 transmembrane segments and is alone responsible for the transport function of the protein. A high-resolution x-ray crystallographic structure has not been determined for the membrane domain. The current study describes a method for the expression and purification of the membrane domain of AE1 expressed in Saccharomyces cerevisiae. The AE1 membrane domain alone, modified with both a 6-His and GST tag, was expressed to 0.5-0.8 mg/l culture. This yeast expression system allows for expression of AE1MD in a eukaryotic membrane, processing through the endoplasmic reticulum for proper folding, and reproducible, large-scale expression and purification of homogeneous protein. |
