Sandbox Reserved 994: Difference between revisions

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== Hydrolysis Mechanism ==
== Hydrolysis Mechanism ==


[[Image:B-lactam hydrolysis3.png|800px|left|thumb|alt=text|β-lactam antibiotics (basic structure of a β-lactam is shown above) are hydrolyzed by β-lactamase enzymes, utilizing a covalent catalysis serine-based mechanism. The β-lactamase cleaves the amide bond of the four membered ring which renders the antibiotic inactive before it reaches its bacterial target, the transpeptidase enzymes.]]
[[Image:B-lactam hydrolysis3.png|800px|none|thumb|alt=text|β-lactam antibiotics (basic structure of a β-lactam is shown above) are hydrolyzed by β-lactamase enzymes, utilizing a covalent catalysis serine-based mechanism. The β-lactamase cleaves the amide bond of the four membered ring which renders the antibiotic inactive before it reaches its bacterial target, the transpeptidase enzymes.]]
 
[[Image:Beta-lactamase resized mechanism.png|500px|none|thumb|alt=text|The mechanism of attack involves a catalytic serine residue, a carboxylated lysine, and another active site serine which contributes to proton movement (A). A high energy tetrahedral intermediate (B) is generated and an acyl enzyme intermediate (C) is formed after the cleavage of the four-membered ring. KCX84 activates the deacylating water which completes the reaction leaving a hydrolyzed β-lactam ring and a regenerated β-lactamase.<ref name="Leonard" />]]




== Catalytic Activity ==
== Catalytic Activity ==
[[Image:Beta-lactamase resized mechanism.png|500px|none|thumb|alt=text|The mechanism of attack involves a catalytic serine residue, a carboxylated lysine, and another active site serine which contributes to proton movement (A). A high energy tetrahedral intermediate (B) is generated and an acyl enzyme intermediate (C) is formed after the cleavage of the four-membered ring. KCX84 activates the deacylating water which completes the reaction leaving a hydrolyzed β-lactam ring and a regenerated β-lactamase.<ref name="Leonard" />]]


There are three catalytic residues involved in the hydrolysis of β-lactam antibiotics. Serine-81 is the catalytic serine, which performs a nucleophilic attack on the β-lactam ring after being deprotonated by the carboxylated lysine-84 (KCX84). This carboxylated lysine is formed by CO2 in the environment engaging in unfavorable interactions with the hydrophobic pocket of OXA-24, so it carboxylates Lysine-84 (A).<ref name="Leonard" />
There are three catalytic residues involved in the hydrolysis of β-lactam antibiotics. Serine-81 is the catalytic serine, which performs a nucleophilic attack on the β-lactam ring after being deprotonated by the carboxylated lysine-84 (KCX84). This carboxylated lysine is formed by CO2 in the environment engaging in unfavorable interactions with the hydrophobic pocket of OXA-24, so it carboxylates Lysine-84 (A).<ref name="Leonard" />
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In step four (D), The enzyme is successfully regenerated and the hydrolyzed β-lactam antibiotic is released back into solution. OXA-24 is now free to hydrolyze another substrate and the antibiotic has been rendered useless.<ref name="Leonard" />  
In step four (D), The enzyme is successfully regenerated and the hydrolyzed β-lactam antibiotic is released back into solution. OXA-24 is now free to hydrolyze another substrate and the antibiotic has been rendered useless.<ref name="Leonard" />  


This is a sample scene created with SAT to <scene name="/12/3456/Sample/1">color</scene> by Group, and another to make <scene name="/12/3456/Sample/2">a transparent representation</scene> of the protein. You can make your own scenes on SAT starting from scratch or by loading and editing one of these sample scenes.
</StructureSection>
== References ==
== References ==
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