Sandbox Reserved 342: Difference between revisions
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<scene name='Sandbox_Reserved_342/Ligands/1'>TextToBeDisplayed</scene> | <scene name='Sandbox_Reserved_342/Ligands/1'>TextToBeDisplayed</scene> | ||
=Function= | =Function= | ||
XGPRT is an enzyme that catalyzes the conversion of guanine, xanthine, and sometimes hypoxanthine, to GMP, XMP, and IMP <ref name="Vos"/>. | XGPRT is an enzyme that catalyzes the conversion of guanine, xanthine, and sometimes hypoxanthine, to GMP, XMP, and IMP <ref name="Vos"/>. This enzyme is part of the purine salvage pathway, which converts exogenous purines (bases or nucleosides) to nucleotides. | ||
<Structure load='1a96' size='300' frame='true' align='right' caption='Insert caption here' scene='Insert optional scene name here' /> | <Structure load='1a96' size='300' frame='true' align='right' caption='Insert caption here' scene='Insert optional scene name here' /> | ||
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<scene name='Sandbox_Reserved_342/Prib-pp_binding_site/3'>Binding site</scene> | <scene name='Sandbox_Reserved_342/Prib-pp_binding_site/3'>Binding site</scene> | ||
=Mechanism= | =Mechanism and Catalysis= | ||
In the large mobile loop of the XGPRT, there are several residues that are critical for substrate binding and catalysis<ref name="Vos"/>. | In the large mobile loop of the XGPRT, there are several residues that are critical for substrate binding and catalysis<ref name="Vos"/>. | ||
Magnesium and other divalent cations are necessary for catalysis because magnesium and PRib-PP binding play a critical role for the PRTase reaction<ref name="Vos"/>. The Mg:PRib-PP complex binds to the active site of PRTases<ref name="Vos"/>. In type I PRTases, XGPRT, catalysis proceeds via SN1 mechanism and it forms a oxocarbonium ion in the transition state<ref name="Vos"/>. It has been suggested, that the magnesium ion departs with the displaced pyrophosphate because there is no magnesium ion at the active site<ref name="Vos"/>. | Magnesium and other divalent cations are necessary for catalysis because magnesium and PRib-PP binding play a critical role for the PRTase reaction<ref name="Vos"/>. The Mg:PRib-PP complex binds to the active site of PRTases<ref name="Vos"/>. In type I PRTases, XGPRT, catalysis proceeds via SN1 mechanism and it forms a oxocarbonium ion in the transition state<ref name="Vos"/>. It has been suggested, that the magnesium ion departs with the displaced pyrophosphate because there is no magnesium ion at the active site<ref name="Vos"/>. | ||