Sandbox Reserved 1846: Difference between revisions
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== Function == | == Function == | ||
LCC catalyzes the hydrolysis of the [https://en.wikipedia.org/wiki/Ester ester] bonds in [https://en.wikipedia.org/wiki/Polymer polymers] of PET, breaking them down into their constituent monomers: terephthalic acid and ethylene glycol.<ref name="Tournier"/> The enzyme operates through a [https://en.wikipedia.org/wiki/Catalytic_triad catalytic triad] that consists of <scene name='10/1075247/Catalytic_triad3_w_label/3'>Ser165, Asp210, and His242</scene>, where a reaction initiated by Ser165 leads to the hydrolysis of ester bonds in PET. During catalysis, the substrate binds in an elongated, predominantly | LCC catalyzes the hydrolysis of the [https://en.wikipedia.org/wiki/Ester ester] bonds in [https://en.wikipedia.org/wiki/Polymer polymers] of PET, breaking them down into their constituent monomers: terephthalic acid and ethylene glycol.<ref name="Tournier"/> The enzyme operates through a [https://en.wikipedia.org/wiki/Catalytic_triad catalytic triad] that consists of <scene name='10/1075247/Catalytic_triad3_w_label/3'>Ser165, Asp210, and His242</scene>, where a reaction initiated by Ser165 leads to the hydrolysis of ester bonds in PET. During catalysis, the substrate binds in an elongated, predominantly <scene name='10/1075246/4eb0_with_colored_ligand_stick/3'>hydrophobic groove</scene> present in the enzyme's structure.<ref name="Sui"/> | ||
LCC functions best at elevated temperatures (around 65–72°C), which approaches the [https://en.wikipedia.org/wiki/Glass_transition glass transition] temperature of PET.<ref name="Zhang">PMID:40028137</ref> This temperature range maximizes PET chain mobility and makes the polymer more accessible to enzymatic action.<ref name="Khairul"/> The enzyme has higher [https://en.wikipedia.org/wiki/Thermostability thermostability] compared to other PET hydrolases, with a [https://en.wikipedia.org/wiki/Melting_point melting temperature] of 84.7°C. This property allows it to remain functional under these high-temperature conditions.<ref name="Burgin"/> Also unlike other PET hydrolases such as Is-PETase, BTA1, BTA2, and FsC, LCC has substantially higher catalytic efficiency.<ref name="Yoshida">PMID:26965627</ref> Specifically, LCC has an initial PET-specific depolymerization rate of 93.2 mg TAeq·h⁻¹·mg⁻¹ enzyme at 65°C with [https://en.wikipedia.org/wiki/Amorphous_solid amorphous] PET. This means that it is at least 33 times more efficient than other tested enzymes.<ref name="Tournier"/><ref name="Khairul"/> LCC's function is limited by PET [https://en.wikipedia.org/wiki/Crystallization_of_polymers crystallinity], as the enzyme can more effectively hydrolyze amorphous regions of the polymer. As PET crystallinity increases during the depolymerization reaction (due to exposure to elevated temperatures), the enzyme's efficiency decreases. This limits complete depolymerization unless optimal conditions and enzyme variants are used.<ref name="Sui"/><ref name="Zhang"/> | LCC functions best at elevated temperatures (around 65–72°C), which approaches the [https://en.wikipedia.org/wiki/Glass_transition glass transition] temperature of PET.<ref name="Zhang">PMID:40028137</ref> This temperature range maximizes PET chain mobility and makes the polymer more accessible to enzymatic action.<ref name="Khairul"/> The enzyme has higher [https://en.wikipedia.org/wiki/Thermostability thermostability] compared to other PET hydrolases, with a [https://en.wikipedia.org/wiki/Melting_point melting temperature] of 84.7°C. This property allows it to remain functional under these high-temperature conditions.<ref name="Burgin"/> Also unlike other PET hydrolases such as Is-PETase, BTA1, BTA2, and FsC, LCC has substantially higher catalytic efficiency.<ref name="Yoshida">PMID:26965627</ref> Specifically, LCC has an initial PET-specific depolymerization rate of 93.2 mg TAeq·h⁻¹·mg⁻¹ enzyme at 65°C with [https://en.wikipedia.org/wiki/Amorphous_solid amorphous] PET. This means that it is at least 33 times more efficient than other tested enzymes.<ref name="Tournier"/><ref name="Khairul"/> LCC's function is limited by PET [https://en.wikipedia.org/wiki/Crystallization_of_polymers crystallinity], as the enzyme can more effectively hydrolyze amorphous regions of the polymer. As PET crystallinity increases during the depolymerization reaction (due to exposure to elevated temperatures), the enzyme's efficiency decreases. This limits complete depolymerization unless optimal conditions and enzyme variants are used.<ref name="Sui"/><ref name="Zhang"/> | ||
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== Structural Overview == | == Structural Overview == | ||
LCC consists of one alpha-beta hydrolase domain, typical of cutinases. In the <scene name='10/1075246/4eb0_helix_sheet/5'>alpha/beta hydrolase fold</scene>, 9 beta-sheets (yellow) form a stable central core with x tilt. | LCC consists of one alpha-beta hydrolase domain, typical of cutinases. In the <scene name='10/1075246/4eb0_helix_sheet/5'>alpha/beta hydrolase fold</scene>, 9 beta-sheets (yellow) form a stable central core with x tilt. | ||
=== Catalytic Triad === | === Catalytic Triad === | ||
[[Image:Final rayed image of binding pocket.png|400 px|right|thumb|Figure 1: Ser, His, Asp catalytic triad non-covalent stabilizing interactions with oxyanion hole.]] | [[Image:Final rayed image of binding pocket.png|400 px|right|thumb|Figure 1: Ser, His, Asp catalytic triad non-covalent stabilizing interactions with oxyanion hole.]] | ||
