Sandbox Reserved 1069: Difference between revisions
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It is important to note that the structure of this binding site is rigid because of the coordination of the zinc between the four residues. This rigidity is indicative that any slight shift on either of the helices will cause a drastic readjustment of the coordination of zinc. In addition, there are no outer-shell constraints to hold the residues in place, which means that with a readjustment of the molecule, there is no energy being expended to bind or release another zinc molecule. Therefore, the zinc is able to rapidly release and a new zinc can bind again with a simple reorientation or shift of the molecule. This rapid on off bind and release mechanism is the regulator of homeostatic levels of zinc in the cell. This regulation is so rapid in fact, it is significantly faster than other zinc exchange rate proteins- by several orders of magnitude. | It is important to note that the structure of this binding site is rigid because of the coordination of the zinc between the four residues. This rigidity is indicative that any slight shift on either of the helices will cause a drastic readjustment of the coordination of zinc. In addition, there are no outer-shell constraints to hold the residues in place, which means that with a readjustment of the molecule, there is no energy being expended to bind or release another zinc molecule. Therefore, the zinc is able to rapidly release and a new zinc can bind again with a simple reorientation or shift of the molecule. This rapid on off bind and release mechanism is the regulator of homeostatic levels of zinc in the cell. This regulation is so rapid in fact, it is significantly faster than other zinc exchange rate proteins- by several orders of magnitude. | ||
[[File:Binding_site_A.fw.png|thumb|Binding Site A showing TM2 domain (left) and TM5 domain (right). The Asp45 and Asp49 as well as the His153 and Asp157 are the coordination residues in the acitve site.]] | |||
'''Binding Site C''' | '''Binding Site C''' | ||