Sandbox Reserved 1053: Difference between revisions

Czr A is a transcriptional repressor protein responsible for the regulation of the '''C'''hromosome Determined '''Z'''inc '''R'''esponsible (Czr) operon. The Czr operon contains genes for the proteins Czr A and Czr B. Czr B is a Zinc transport protein which moves Zinc out of a cell. Czr A regulates this process by controlling the degree to which Czr B is expressed. When relatively low amounts of zinc are present in the cell Czr A will bind to DNA, inhibiting expression of Czr B, enabling the cell to retain Zinc. When high amounts of Zinc 2+ are present in the cell, each Czr A molecule binds two Zn 2+ ions, and forcing a conformational change. The zinc binding conformation of Czr A is not capable of binding to DNA, as the new conformation disrupts the DNA binding pocket. Conversely, the DNA binding conformation of Czr A does not allow for the binding of either Zn 2+ atom.