Sandbox Reserved 1066

Zn Transporter YiiP

spinqualitylabelsall models Zn Transporter Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D This is a default text for your page Kyle Colston/Sandbox 1. Click above on edit this page to modify. Be careful with the < and > signs. You may include any references to papers as in: the use of JSmol in Proteopedia or to the article describing Jmol to the rescue. Organism This protein is found in E. coli Structure YiiP is a homodimer with transmembrane (TMD) and C-terminal (CTD) domains that are connected via a charge interlocking mechanism located on a flexible loop. There are 3 Zn2+ binding sites per unit of homodimer. Site A is located in the TMD, site C is located in the CTD, and site B is located at the junction of the domains join. Both TMD are composed of 6 helices, 4 of which (TM1,TM2,TM4,TM5) form a pore in which Zn2+ and H+ can reach binding Site A. Zn2+ binding at site C helps hold the CTD together and is thought to stabilize conformational changes in YiiP. Mechanism of Transport YiiP's ability to export Zn2+ from the cytoplasm is best described as an alternating access mechanism with Zn2+/H+ antiport. YiiP has 2 major structural conformations which is supported by the crystallized structures 3H90 and 3J1Z (a YiiP homolog derived from Shewanella oneidensis). 3H90 shows YiiP in its outward-facing conformation and 3J1Z shows the YiiP homolog in an inward-facing conformation. The energy for inducing the conformation change from inward to outward is postulated to come from the binding energy of each substrate. The binding of Zn2+ favors the outward-facing conformation, but the outward facing conformation does not favor the binding of Zn2+. The same is observed with the inward-facing conformation and H+. Although YiiP exists as a homodimer both monomers can undergo conformation change independent of one other to produce the alternating access mechanism. The main driving force behind exporting Zn2+ from the cytoplasm is the proton motive force. Allosteric Inhibition Zn binding to Active Site C causes a conformation change that reduces the affinity for Zn at Active Site A. Structural highlights This is a sample scene created with SAT to color by Group, and another to make a transparent representation of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.