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Updated: Aug 6, 2026
05:58
Site-Specific Lysine Lactylation via Genetic Code Expansion in E. coli and Mammalian Cells
Published on: February 24, 2026
Double deletion mutation induced active site remodelling modulates substrate specificity in KPC-14 β-lactamase
Lin Gao1, Jaeyin Yoo1, Enus Fina1
1UCL School of Pharmacy, University College London, London, UK.
International Journal of Biological Macromolecules
|July 23, 2026
Summary
A new KPC-14 variant shows resistance to certain antibiotics due to structural changes. These alterations affect its catalytic activity and substrate specificity, impacting β-lactam antibiotic therapy effectiveness.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Klebsiella pneumoniae carbapenemase (KPC) variants present challenges in antibiotic therapy.
- KPC-14 exhibits increased resistance to ceftazidime and ceftazidime-avibactam but reduced carbapenemase activity.
- The structural basis for KPC-14's altered catalytic behavior is not well understood.
Purpose of the Study:
- To investigate the conformational effects of the double deletion (Y241_ΔGT_A244) in KPC-14.
- To elucidate the structural basis for KPC-14's altered substrate specificity and catalytic activity.
- To understand how structural perturbations influence the catalytic landscape of class A β-lactamases.
Main Methods:
- Machine learning-enhanced sampling molecular dynamics simulations.
- Unsupervised deep learning analysis (convolutional variational autoencoder).
- Molecular docking studies.
Main Results:
- The double deletion in KPC-14 increases the flexibility of key loops (Ω-loop, 237-243, 266-275).
- Distinct conformational landscapes were identified for KPC-14 and KPC-2, with KPC-14 showing three dominant states.
- Deletion-induced repositioning of Y241 disrupts hydrophobic packing, alters active site residues (S70, E166, H274), and reshapes the catalytic environment.
- KPC-14 conformations accommodate ceftazidime more readily in catalytically competent geometries.
Conclusions:
- Structural changes in KPC-14 impact carbapenem hydrolysis efficiency by altering catalytic geometry.
- The enlarged active site cavity in KPC-14 facilitates accommodation of oxyimino-cephalosporin side chains.
- These findings provide a mechanistic explanation for KPC-14's altered substrate specificity and resistance profile.
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