Sandbox 124: Difference between revisions
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'''Cell Wall Structure''' | ==='''Cell Wall Structure'''=== | ||
The cell wall, which is composed of peptidoglycans, is crucial for maintaining | The cell wall, which is composed of peptidoglycans, is crucial for maintaining | ||
the structural integrity of the bacterium. Peptidoglycans consists of | the structural integrity of the bacterium. Peptidoglycans consists of | ||
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==='''Catalytic Mechanism of PBP2a'''=== | ==='''Catalytic Mechanism of PBP2a'''=== | ||
[[Image:Schematic TP 3steps.jpg|thumb|alt= Alt text| |550px]] | [[Image:Schematic TP 3steps.jpg|thumb|alt= Alt text|Figure 2. Schematic showing Catalytic Mechanism of PBP2a |550px]] | ||
(a) The D-Ala-D-Ala side-chain substrate of the peptidoglycan accesses | (a) The D-Ala-D-Ala side-chain substrate of the peptidoglycan accesses | ||
the active site of the PBP2a. | the active site of the PBP2a. | ||
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The entire process takes 4 milliseconds. | The entire process takes 4 milliseconds. | ||
==='''How | ==='''How Do Antibiotics Work?'''=== | ||
The β-lactam antibiotics inhibit bacterial growth by inhibiting PBPs and ultimately cell wall | The β-lactam antibiotics inhibit bacterial growth by inhibiting PBPs and ultimately cell wall | ||
synthesis. Specifically, β-lactams are molecular mimics of D-Ala-D-Ala, which is the normal | synthesis. Specifically, β-lactams are molecular mimics of D-Ala-D-Ala, which is the normal | ||
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inhibited by the β-lactam. As a result, the synthesis of the cell wall is inhibited which leads | inhibited by the β-lactam. As a result, the synthesis of the cell wall is inhibited which leads | ||
to cell lysis. | to cell lysis. | ||
[[Image:Structures on penicillin and b lactam.jpg|thumb|alt= Alt text|Figure 3. Mechanism of action of β-lactams. A. Structure of a β-lactam (penicillin) showing the amide, carboxyl, and β-lactam ring groups β-lactam ring groups. B. Structure of the D-Ala-D-Ala substrate. C. Overlay of the D-Ala-D-Ala substrate in red with penicillin demonstrating molecular mimicry.|550 px]] | |||
==='''PBP2a and Ceftobiprole'''=== | ==='''PBP2a and Ceftobiprole'''=== | ||
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residues in PBP2a; specifically | residues in PBP2a; specifically | ||
<scene name='37/372724/Tyr446_and_met641_label/2'>Tyr446 and Met641</scene>. | <scene name='37/372724/Tyr446_and_met641_label/2'>Tyr446 and Met641</scene>. | ||
As a result of | As a result of ceftobiprole <scene name='37/372724/R2_interaction/4'>tighter binding</scene> to PBP2a as highlighted in green , <scene name='37/372724/Ceftobiprole_in_cpk/1'>the medicine</scene>, shown as colors of the atom types ([[CPK]]), is able to more efficiently react with the serine active site residue and therefore inhibit the activity of PBP2a. | ||