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Updated: Jan 7, 2026
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Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics
Published on: October 13, 2020
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Peptidoglycan LD-Transpeptidases
Samuel Gastrell1, Waldemar Vollmer1
1Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia.
Antibiotics (Basel, Switzerland)
|December 30, 2025
Summary
LD-transpeptidases (LDTs) are crucial bacterial enzymes, essential for pathogen survival and β-lactam resistance. Targeting LDTs offers a promising strategy for developing new antibiotic treatments against resistant bacteria.
Area of Science:
- Microbiology
- Biochemistry
- Structural Biology
Background:
- LD-transpeptidases (LDTs) are conserved bacterial enzymes involved in peptidoglycan (PG) crosslinking, often acting secondary to penicillin-binding proteins (PBPs).
- LDTs are critical in pathogens like *Clostridioides difficile* and confer β-lactam resistance in *Mycobacterium tuberculosis* and *Enterococcus faecium* due to their low affinity for common antibiotics.
- Their ability to form LD-crosslinks when PBPs are inhibited makes LDTs attractive therapeutic targets.
Purpose of the Study:
- To elucidate the diverse enzymatic functions and roles of LD-transpeptidases in bacterial cell wall synthesis and integrity.
- To explore the potential of LDTs as targets for novel antibiotic development against resistant pathogens.
- To investigate recent discoveries, including new LDT subgroups, to expand research into PG synthesis and modification.
Main Methods:
- Comparative analysis of LDT sequences and structures.
- Enzymatic assays to characterize LDT activity (e.g., crosslinking, D-amino acid incorporation).
- Investigating the role of LDTs in cell envelope integrity and virulence in various bacterial species.
Main Results:
- LDTs reinforce PG via 3,3-LD- or 1,3-LD-crosslinks, particularly under stress conditions.
- Some LDTs incorporate non-canonical D-amino acids into PG.
- Specialized LDTs in Gram-negative bacteria are involved in tethering outer membrane proteins and regulating virulence.
Conclusions:
- LD-transpeptidases play multifaceted roles beyond simple PG crosslinking, including stress response and cell envelope maintenance.
- The identification of novel LDT families (e.g., VanW) and subgroups expands the understanding of their diversity and function.
- Targeting LDTs presents a viable strategy for combating antibiotic resistance and developing new antimicrobial therapies.
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