Degradation of biogene oligosaccharides by β-N-acetylglucosaminidase secreted by Entamoeba histolytica

Werries, Eckhard; Nebinger, Peter; Franz, Alfred

doi:10.1016/0166-6851(83)90040-3

Cited by 19 publications

(7 citation statements)

References 18 publications

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“…An understanding of the functional roles of the Mycetozoan proteins which provide one with best candidates for the most ancient divergence in the eukaryote tree might be the key to understanding the nature of the ancestral enzyme activity. However, functional characterization of the slime mould Dictyostelium GH20 protein has not been published and biochemical data of the β-N-acetylglucosaminidases of Entamoeba histolytica do not allow strong inference as to the substrate specificity of these amoebozoan enzymes [79]. Furthermore, although we have observed high conservation of amino acids involved in substrate binding (see above), a crystal structure of a β-hexosaminidase involved in paucimannosidic N -glycans formation might provide precise information about the characteristics of active sites of β-hexosaminidases that display exochitinase activity.…”

Section: Resultsmentioning

confidence: 99%

Phylogenetic analyses suggest multiple changes of substrate specificity within the Glycosyl hydrolase 20 family

2008

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BackgroundBeta-N-acetylhexosaminidases belonging to the glycosyl hydrolase 20 (GH20) family are involved in the removal of terminal β-glycosidacally linked N-acetylhexosamine residues. These enzymes, widely distributed in microorganisms, animals and plants, are involved in many important physiological and pathological processes, such as cell structural integrity, energy storage, pathogen defence, viral penetration, cellular signalling, fertilization, development of carcinomas, inflammatory events and lysosomal storage diseases. Nevertheless, only limited analyses of phylogenetic relationships between GH20 genes have been performed until now.ResultsCareful phylogenetic analyses of 233 inferred protein sequences from eukaryotes and prokaryotes reveal a complex history for the GH20 family. In bacteria, multiple gene duplications and lineage specific gene loss (and/or horizontal gene transfer) are required to explain the observed taxonomic distribution. The last common ancestor of extant eukaryotes is likely to have possessed at least one GH20 family member. At least one gene duplication before the divergence of animals, plants and fungi as well as other lineage specific duplication events have given rise to multiple paralogous subfamilies in eukaryotes. Phylogenetic analyses also suggest that a second, divergent subfamily of GH20 family genes present in animals derive from an independent prokaryotic source. Our data suggest multiple convergent changes of functional roles of GH20 family members in eukaryotes.ConclusionThis study represents the first detailed evolutionary analysis of the glycosyl hydrolase GH20 family. Mapping of data concerning physiological function of GH20 family members onto the phylogenetic tree reveals that apparently convergent and highly lineage specific changes in substrate specificity have occurred in multiple GH20 subfamilies.

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Section: Resultsmentioning

confidence: 99%

Phylogenetic analyses suggest multiple changes of substrate specificity within the Glycosyl hydrolase 20 family

2008

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“…E. histolytica contains proteolytic enzymes (collagenase and neutral proteases) and cysteine proteases, which presumably facilitate its tissue invasion. The parasite also elaborates a range of enzymes on the amebic surface, including membrane-associated neuraminidase and ␤-glucosaminidase (166,223,234). There is a correlation between the virulence of E. histolytica and the secretion of electron-dense granules (26).…”

Section: Pathogenicitymentioning

confidence: 99%

Laboratory Diagnosis of Amebiasis

2003

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The detection of Entamoeba histolytica, the causative agent of amebiasis, is an important goal of the clinical microbiology laboratory. To assess the scope of E. histolytica infection, it is necessary to utilize accurate diagnostic tools. As more is discovered about the molecular and cell biology of E. histolytica, there is great potential for further understanding the pathogenesis of amebiasis. Molecular biology-based diagnosis may become the technique of choice in the future because establishment of these protozoa in culture is still not a routine clinical laboratory process. In all cases, combination of serologic tests with detection of the parasite (by antigen detection or PCR) offers the best approach to diagnosis, while PCR techniques remain impractical in many developing country settings. The detection of amebic markers in serum in patients with amebic colitis and liver abscess appears promising but is still only a research tool. On the other hand, stool antigen detection tests offer a practical, sensitive, and specific way for the clinical laboratory to detect intestinal E. histolytica. All the current tests suffer from the fact that the antigens detected are denatured by fixation of the stool specimen, limiting testing to fresh or frozen samples

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“…Glycosidase activities detected in E. histolytica include glucosidase (99,150,160), galactosidase (150,160), mannosidase (160), fucosidase (150,160), xylosidase (150,160), glucuronidase (160), N-acetyl-D-glucosaminidase (14,99,150,160,176), N-acetyl-D-galactosaminidase (14,150), N-acetylneuraminate lyase (160), neuraminidase (160,165), amylase (99,160), and hyaluronidase (160). Glycosidases are generally more active at acidic pH, suggesting their lysosomal origin.…”

Section: Mucopenic Depressionmentioning

confidence: 99%