zinc transporter structure (IMAGE) DOE/Brookhaven National Laboratory Caption Overall structure of a transmembrane ZIP zinc transporter protein determined by cryo-electron microscopy (cryo-EM) (left) and a schematic showing some of the functional features (right). A flexible loop (magenta) facing into the cell binds to zinc and folds to block the entry of more zinc when levels of this micronutrient get too high. Credit Brookhaven National Laboratory Usage Restrictions OK for use with stories about this research License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.