Are there biological functions for bacterial endo-N-acetyl-β-D-glucosaminidases?

Karamanos, Yannis; Bourgerie, S; Barreaud, Jean-Pierre; Julien, Raymond

doi:10.1016/0923-2508(96)80289-0

Cited by 15 publications

(9 citation statements)

References 36 publications

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“…As well as functioning in chitin degradation by bacteria, GlcNAcases are also known to be key enzymes in the catabolism of glycoconjugates containing N -acetylglucosamine residues [7,8] and mutations of the gene encoding a human GlcNAcase homologue (HexA) cause a fatal genetic lipid storage disorder, known as Tay-Sachs disease [9]. In the CAZy database (http://www.cazy.org), GlcNAcases are classified into glycosyl hydrolases family 3 (GH-3) or family 20 (GH-20), which differ in sequence and mode of enzyme action [10,11].…”

Section: Introductionmentioning

confidence: 99%

Novel β-N-acetylglucosaminidases from Vibrio harveyi 650: Cloning, expression, enzymatic properties, and subsite identification

et al. 2010

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BackgroundSince chitin is a highly abundant natural biopolymer, many attempts have been made to convert this insoluble polysaccharide into commercially valuable products using chitinases and β-N-acetylglucosaminidases (GlcNAcases). We have previously reported the structure and function of chitinase A from Vibrio harveyi 650. This study t reports the identification of two GlcNAcases from the same organism and their detailed functional characterization.ResultsThe genes encoding two new members of family-20 GlcNAcases were isolated from the genome of V. harveyi 650, cloned and expressed at a high level in E. coli. VhNag1 has a molecular mass of 89 kDa and an optimum pH of 7.5, whereas VhNag2 has a molecular mass of 73 kDa and an optimum pH of 7.0. The recombinant GlcNAcases were found to hydrolyze all the natural substrates, VhNag2 being ten-fold more active than VhNag1. Product analysis by TLC and quantitative HPLC suggested that VhNag2 degraded chitooligosaccharides in a sequential manner, its highest activity being with chitotetraose. Kinetic modeling of the enzymic reaction revealed that binding at subsites (-2) and (+4) had unfavorable (positive) binding free energy changes and that the binding pocket of VhNag2 contains four GlcNAc binding subsites, designated (-1),(+1),(+2), and (+3).ConclusionsTwo novel GlcNAcases were identified as exolytic enzymes that degraded chitin oligosaccharides, releasing GlcNAc as the end product. In living cells, these intracellular enzymes may work after endolytic chitinases to complete chitin degradation. The availability of the two GlcNAcases, together with the previously-reported chitinase A from the same organism, suggests that a systematic development of the chitin-degrading enzymes may provide a valuable tool in commercial chitin bioconversion.

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Section: Introductionmentioning

confidence: 99%

Novel β-N-acetylglucosaminidases from Vibrio harveyi 650: Cloning, expression, enzymatic properties, and subsite identification

et al. 2010

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“…Remarkably, the N ‐acetyl‐β‐ d ‐glucosaminidase activity showed a reduction in the cytoplasmic protein extracts, and an increase in the extracellular milieu, when the cells were grown in the presence of mucus. Bacterial N ‐acetyl‐β‐ d ‐glucosaminidases are glycoprotein‐degrading enzymes that have been related to the colonization of mucus environments (Homer et al , 1994; Karamanos et al , 1995). The increase of the secreted activity in the presence of mucus could support the possible role of this enzyme in mucus degradation.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of the ability of Bifidobacterium longum to metabolize human intestinal mucus

Ruíz

Gueimonde

Couté

et al. 2010

FEMS Microbiology Letters

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The ability of Bifidobacterium longum to use intestinal mucus as a metabolizable source was characterized. Bifidobacterium longum biotype longum NCIMB8809 was grown in a chemically semi-defined medium supplemented with human intestinal mucus, and the cytoplasmic protein profiles and several glycosyl hydrolase activities were analysed and compared with those obtained from the same bacterium grown in the absence of mucus. We were able to identify 22 different proteins in the cytoplasmic fraction, of which nine displayed a different concentration in the presence of mucus. Among the proteins whose concentrations varied, we found specific enzymes that are involved in the response to different environmental conditions, and also proteins that mediate interaction with mucus in bacteria. Significant changes in some glycoside-hydrolysing activities were also detected. In addition, stable isotope labelling of amino acids in cell culture demonstrated that B. longum incorporates leucine from the glycoprotein matrix of mucin within its proteins. This study provides the first proteomic data regarding the interaction of B. longum with intestinal mucus, and contributes to the understanding of the behaviour of this intestinal species in its natural ecological niche.

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“…N-glycans represent the oligosaccharide moieties of N-glycosylproteins which are major components of all animal, plant and fungal cells and many viruses. N-glycan-ENGases were shown to be produced by many bacteria and also to be generally secreted but seeing that N-glycosylproteins were not identified and characterised in bacteria, we have hypothesised [177] that the enzymes were probably devoted to exogenous functions, such as degrading macromolecules for feeding purposes and also stated that the bacterial N-glycan-ENGases could be considered as markers of cell events. N-glycosylproteins were also described in bacteria and over the last decade considerable progress has been made in the understanding of bacterial N-glycosylation systems [178].…”

Section: Concluding Remarks and Future Prospectsmentioning

confidence: 99%

Endo-N-Acetyl-β-D-Glucosaminidases and Peptide-N4-(N-acetyl-β-D-Glucosaminyl) Asparagine Amidases: More Than Just Tools

Karamanos¹

2013

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Abstract:Since the discovery of endo-N-acetyl-β-D-glucosaminidases (ENGase) and peptide-N4-(N-acetyl-β-D-glucosaminyl) asparagine amidases (PNGase) most of the published work described their use for structural studies. Less attention was given to the potential roles of those enzymes in the physiology of the cells/organisms they produced them. The scope of this review is firstly to analyse the data on the occurrence and characteristics of murein-, chitin-, and N-glycan-ENGases acting on GlcNAc-containing polymers in three structural families, namely murein, chitin, and N-glycosylproteins, and of PNGases, only acting on N-glycosylproteins, and secondly to discuss the biological roles of the enzymes in the producing cells. The analysis demonstrates the remarkable diversity of the enzymes, and simultaneously the interest of studying their substrate specificity and their structural features. Many examples illustrate the importance of the structure/function relationships studies. Diverse biological roles were anticipated, e.g. they are useful for feeding purposes, are implicated in pathogenesis processes, modulate the activity of macromolecules, and help in the destruction of misfolded proteins. Their effect can be direct or indirect, through the reaction products. Current knowledge only partially explains the biological roles of ENGases and PNGases, thus further studies are expected for determining novel possibilities and elucidating other cell pathways.

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Are there biological functions for bacterial endo-N-acetyl-β-D-glucosaminidases?

Cited by 15 publications

References 36 publications

Novel β-N-acetylglucosaminidases from Vibrio harveyi 650: Cloning, expression, enzymatic properties, and subsite identification

Novel β-N-acetylglucosaminidases from Vibrio harveyi 650: Cloning, expression, enzymatic properties, and subsite identification

Evaluation of the ability of Bifidobacterium longum to metabolize human intestinal mucus

Endo-N-Acetyl-β-D-Glucosaminidases and Peptide-N4-(N-acetyl-β-D-Glucosaminyl) Asparagine Amidases: More Than Just Tools

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