Sandbox Reserved 1066: Difference between revisions

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 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.