Sandbox Reserved 1846: Difference between revisions
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=== Catalytic Triad === | === Catalytic Triad === | ||
LCC catalyzes the breakdown of PET using a classic serine hydrolase mechanism involving a catalytic triad of Ser165, His242, and Asp210. The reaction begins when His242 deprotonates Ser165, which activates it as a nucleophile. Ser165 then attacks the carbonyl carbon of an ester bond in the PET polymer. This forms a tetrahedral intermediate. This intermediate is stabilized by an oxyanion hole. The intermediate collapses; one product is released and an acyl-enzyme intermediate is formed. A water molecule, activated by His242, then attacks the acyl-enzyme, releasing the second product and resetting the enzyme’s active site. | LCC catalyzes the breakdown of PET using a classic serine hydrolase mechanism involving a catalytic triad of Ser165, His242, and Asp210. The reaction begins when His242 deprotonates Ser165, which activates it as a nucleophile. Ser165 then attacks the carbonyl carbon of an ester bond in the PET polymer. This forms a tetrahedral intermediate. This intermediate is stabilized by an oxyanion hole. The oxyanion hole is formed by the backbone amides of Met166 and Tyr95. The intermediate collapses; one product is released and an acyl-enzyme intermediate is formed. A water molecule, activated by His242, then attacks the acyl-enzyme, releasing the second product and resetting the enzyme’s active site. | ||
[[Image:Mechanism_(1).jpeg|1100 px]] | [[Image:Mechanism_(1).jpeg|1100 px]] | ||
=== Ligand Binding Pocket === | === Ligand Binding Pocket === | ||
The substrate-binding site of LCC is a long, mainly hydrophobic groove that accommodates PET chains. This groove includes three subsites—designated −2, −1, and +1—that interact with specific PET units near the scissile ester bond. Hydrophobic residues such as F125, V212, M166, and F243 line the groove and facilitate binding by interacting with the aromatic rings of the PET molecule. These interactions help align the substrate in the correct position for catalysis. | |||
== Mutation Sites of Interest == | == Mutation Sites of Interest == | ||
