The exo-β-N-acetylmuramidase NamZ from Bacillus subtilis is the founding member of a family of exo-lytic peptidoglycan hexosaminidases
| Autor: | Alexander Titz, Qingping Xu, Marina Borisova, Alicia Engelbrecht, Isabel Hottmann, Christoph Mayer, Maraike Müller, Matthew B. Calvert, Robert Maria Kluj, Khaled A. Selim, Tim Teufel, Katja Balbuchta |
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| Přispěvatelé: | HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. |
| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
CAZy Protein family Glycoside Hydrolases peptidoglycan hydrolase Protein Conformation pNP-GlcNAc para-nitrophenyl 2-acetamido-2-deoxy-β-d-glucopyranoside Bacillus subtilis Peptidoglycan cell wall recycling AUC area under curve Crystallography X-Ray Biochemistry N-acetylmuramidase Acetylglucosamine 03 medical and health sciences chemistry.chemical_compound N-Acetylglucosamine Molecular Biology lysozyme BPC base peak chromatogram exo-lytic glycosidase 030102 biochemistry & molecular biology biology Chemistry Hydrolysis pNP-MurNAc para-nitrophenyl 2-acetamido-3-O-(d-1-carboxyethyl)-2-deoxy-β-D-glucopyranoside Cell Biology GlcNAc N-acetylglucosamine biology.organism_classification Rossmann-fold Hexosaminidases EIC extracted ion chromatogram carbohydrates (lipids) 030104 developmental biology N-Acetylmuramic acid Muramic Acids N-acetylglucosaminidase Lysozyme MurNAc N-acetylmuramic acid Research Article N-acetylmuramoyl amidase |
| Zdroj: | The Journal of Biological Chemistry The Journal of biological chemistry United States |
| ISSN: | 1083-351X |
| Popis: | Endo-β-N-acetylmuramidases, commonly known as lysozymes, are well-characterized antimicrobial enzymes that catalyze an endo-lytic cleavage of peptidoglycan; i.e., they hydrolyze the β-1,4-glycosidic bonds connecting N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc). In contrast, little is known about exo-β-N-acetylmuramidases, which catalyze an exo-lytic cleavage of β-1,4-MurNAc entities from the non-reducing ends of peptidoglycan chains. Such an enzyme was identified earlier in the bacterium Bacillus subtilis, but the corresponding gene has remained unknown so far. We now report that ybbC of B. subtilis, renamed namZ, encodes the reported exo-β-N-acetylmuramidase. A ΔnamZ mutant accumulated specific cell wall fragments and showed growth defects under starvation conditions, indicating a role of NamZ in cell wall turnover and recycling. Recombinant NamZ protein specifically hydrolyzed the artificial substrate para-nitrophenyl β-MurNAc and the peptidoglycan-derived disaccharide MurNAc-β-1,4-GlcNAc. Together with the exo-β-N-acetylglucosaminidase NagZ and the exo-muramoyl-l-alanine amidase AmiE, NamZ degraded intact peptidoglycan by sequential hydrolysis from the non-reducing ends. A structure model of NamZ, built on the basis of two crystal structures of putative orthologs from Bacteroides fragilis, revealed a two-domain structure including a Rossmann-fold-like domain that constitutes a unique glycosidase fold. Thus, NamZ, a member of the DUF1343 protein family of unknown function, is now classified as the founding member of a new family of glycosidases (CAZy GH171; www.cazy.org/GH171.html). NamZ-like peptidoglycan hexosaminidases are mainly present in the phylum Bacteroidetes and less frequently found in individual genomes within Firmicutes (Bacilli, Clostridia), Actinobacteria, and γ-proteobacteria. |
| Databáze: | OpenAIRE |
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