Sandbox 122
New Delhi Metallo-Beta-LactamaseNew Delhi Metallo-Beta-Lactamase
The New Delhi metallo-beta-lactamse in complex with meropenem demonstrates the mechanism in which the active site binds and hydrolyzes the carbapenem, in this case meropenem. Zn1, coordinated by three histidine residues, acts as a major constituent of oxyanion hole to stabilize tetrahedral intermediate. It also acts as a Lewis acid for interaction with lactam carbonyl in Michaelis complex. Zn1 also acts to suppress the pka of the hydrolytic water to (~5-6) to facilitate it's nucleophillic role.
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The NDM-1 is a metallo-protein and associated with the bacterial cell membrane. The active site contains key features for hydrolyzing carbapenems:
- Zinc ion 1(Zn1) is coordinated by three histidine residues: H120, H122 and H189
- Zinc ion (Zn2) is coordinated by three residues: H250, C208 and D124