Sandbox Reserved 1767: Difference between revisions
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== Structure of Active Site == | == Structure of Active Site == | ||
=== 3-Metal Ion Catalysis === | === 3-Metal Ion Catalysis === | ||
<scene name='95/952695/Pp1c_active_site/1'>Catalytic Active Site</scene> | The <scene name='95/952695/Pp1c_active_site/1'>Catalytic Active Site</scene> of the SHOC2-PP1C-MRAS complex resides in the PP1C subunit. The role of PP1C is to dephosphorylate SER259 of Raf so that the signaling cascade can start. The active site is unchanged upon the binding of the complex, however, SHOC2 and MRAS aid in the specificity of the enzymatic activity as PP1C is able to dephosphorylate many different targets on its own, with almost 100 PP1C targets found. The full mechanism for the catalytic activity is unknown, however, there are 3 metal ions present (2-Mg2+ and 1-Cl-) to stabilize the waters present in the active site. Additionally, the substrate binds through hydrogen bonds with the main chain and side chain atoms of the catalytic residues. Mutations in the active site lead to increased activity, causing the Ras/Raf signaling cascade to be triggered more frequently. | ||
=== Hydrophobic Binding Site === | === Hydrophobic Binding Site === | ||
PP1C has a hydrophobic binding site adjacent to its active site. The majority of PP1C targets are able to bind through a specific motif that is recognized by the hydrophobic groove. In the Ras/Raf signaling cascade, the region of Raf that is C-terminal to the phosphate group binds to the hydrophobic groove, and the remaining residues bind to the hydrophobic region of SHOC2. This binding to SHOC2 is what allows the SMP complex to be more specific than PP1C on its own. | |||
== Future Directions == | == Future Directions == | ||
