Download MendeleyA distinctive family of L,D-transpeptidases catalyzing L-Ala-mDAP crosslinks in Alpha- and Betaproteobacteria.
Espaillat, A., Alvarez, L., Torrens, G., Ter Beek, J., Miguel-Ruano, V., Irazoki, O., Gago, F., Hermoso, J.A., Berntsson, R.P., Cava, F.(2024) Nat Commun 15: 1343-1343
- PubMed: 38351082
- DOI: https://doi.org/10.1038/s41467-024-45620-5
- Primary Citation of Related Structures:
8QZG - PubMed Abstract:
The bacterial cell-wall peptidoglycan is made of glycan strands crosslinked by short peptide stems. Crosslinks are catalyzed by DD-transpeptidases (4,3-crosslinks) and LD-transpeptidases (3,3-crosslinks). However, recent research on non-model species has revealed novel crosslink types, suggesting the existence of uncharacterized enzymes. Here, we identify an LD-transpeptidase, LDT Go , that generates 1,3-crosslinks in the acetic-acid bacterium Gluconobacter oxydans. LDT Go -like proteins are found in Alpha- and Betaproteobacteria lacking LD3,3-transpeptidases. In contrast with the strict specificity of typical LD- and DD-transpeptidases, LDT Go can use non-terminal amino acid moieties for crosslinking. A high-resolution crystal structure of LDT Go reveals unique features when compared to LD3,3-transpeptidases, including a proline-rich region that appears to limit substrate access, and a cavity accommodating both glycan chain and peptide stem from donor muropeptides. Finally, we show that DD-crosslink turnover is involved in supplying the necessary substrate for LD1,3-transpeptidation. This phenomenon underscores the interplay between distinct crosslinking mechanisms in maintaining cell wall integrity in G. oxydans.
Organizational Affiliation:
Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden.
