Search results for "Glycosyl"
showing 10 items of 317 documents
Synthesis of Fluorinated Glycosyl Amino Acid Building Blocks for MUC1 Cancer Vaccine Candidates by Microreactor-Assisted Glycosylation
2012
Abstract MUC1-type glycopeptides have already shown their potential as possible cancer vaccine candidates. In addition, first examples of fluorinated antigen structures, especially containing the Thomsen–Friedenreich antigen, with similar antibody recognition have been reported. Using microreactor techniques for improvement of the crucial step, the complex glycosylation reactions, is an efficient way to find optimized reaction parameter as well as to circumvent well-known scale-up drawbacks. Besides, this is the first report of continuous flow glycosylations of glycosyl amino acids, in particular with fluorinated glycosyl building blocks.
Cell Wall and Secreted Proteins ofCandida albicans: Identification, Function, and Expression
1998
SUMMARYThe cell wall is essential to nearly every aspect of the biology and pathogenicity of Candida albicans. Although it was intially considered an almost inert cellular structure that protected the protoplast against osmotic offense, more recent studies have demonstrated that it is a dynamic organelle. The major components of the cell wall are glucan and chitin, which are associated with structural rigidity, and mannoproteins. The protein component, including both mannoprotein and nonmannoproteins, comprises some 40 or more moieties. Wall proteins may differ in their expression, secretion, or topological location within the wall structure. Proteins may be modified by glycosylation (prima…
Synthetic O-glycopeptides as model substrates for glycosyltransferases
1993
Abstract A new approach to O-glycopeptides of the glucosamine type is described. N-Urethane protected, peracetylated glucosamine is converted into its 1-thio (1-bromo) derivative and used for glycosylation of a variety of protected serine or threonine derivatives as acceptors. The urethane group is easily exchanged for the natural N-acetyl moiety and O-deacetylation is achieved with hydrazine/methanol. The resulting O-GlcNAc derivatives are subjected to an enzymatic galactosylation procedure using β-1,4-galactosyltransferase (EC 2.4.1.22) to furnish O-glycopeptides of the neolactosamine type.
Glycosylated macromolecular conjugates of antiviral drugs with a polyaspartamide.
2004
Two new polymeric conjugates for specific liver targeting were prepared by conjugation of sugar moieties and antiviral drugs to alpha, beta-poly[N-2-(hydroxyethyl)-DL-aspartamide] (PHEA). PHEA-galactopyranosylphenylthiocarbamide-mono-O-succinylganciclovir (conjugate 7) and PHEA-mannopyranosylphenylthiocarbamide-O-succinylacyclovir (conjugate 8) were synthesized according to a multi-step procedure which allowed for obtaining high product yield and process standardization. Conjugate 7 contained 7.5 and 8.5% of galactose and ganciclovir (substituent/repeating unit, mol/mol), respectively, and conjugate 8 contained 14.2 and 10.8% of mannose and acyclovir, respectively. In vitro studies demonstr…
Posttranslational N-glycosylation of the hepatitis B virus large envelope protein
2007
Abstract Background The addition of N-linked glycans to proteins is normally a cotranslational process that occurs during translocation of the nascent protein to the endoplasmic reticulum. Here, we report on an exception to this rule occurring on the hepatitis B virus (HBV) large L envelope protein that is a subject to co-plus posttranslational N-glycosylation. Results By using an improved detection system, we identified so far unrecognized, novel isoforms of L. Based on mutational analyses, the use of N-glycosylation inhibitors, and pulse-chase studies, we showed that these isoforms are due to posttranslational N-glycan addition to the asparagines 4 and 112 within the preS domain of L. Whi…
Expression pattern of the Brachyury and Tbx2 homologues from the sponge Suberites domuncula.
2005
Background information. T-box transcription factors are a large family of transcriptional regulators involved in many aspects of embryonic development. In a previous report, we described the isolation and genomic characterization of two T-box genes from the siliceous sponge Suberites domuncula: a Brachyury homologue, Sd-Bra, and a Tbx2 homologue, Sd-Tbx2. Elucidation of the genomic structure of Sd-Bra allowed us to demonstrate the existence of two different isoforms, resulting from alternative splicing. Moreover, we demonstrated that the shorter isoform exists in two different glycosylation states. Results. In the present study, we demonstrate a differential subcellular localization of the …
Glycosylation deficiency at either one of the two glycan attachment sites of cellular prion protein preserves susceptibility to bovine spongiform enc…
2004
The conversion into abnormally folded prion protein (PrP) plays a key role in prion diseases. PrP(C) carries two N-linked glycan chains at amino acid residues 180 and 196 (mouse). Previous in vitro data indicated that the conversion process may not require glycosylation of PrP. However, it is conceivable that these glycans function as intermolecular binding sites during the de novo infection of cells on susceptible organisms and/or play a role for the interaction of both PrP isoforms. Such receptor-like properties could contribute to the formation of specific prion strains. However, in earlier studies, mutations at the glycosylation sites of PrP led to intracellular trafficking abnormalitie…
Heterodimerization of Two Pathological Mutants Enhances the Activity of Human Phosphomannomutase2
2015
The most frequent disorder of glycosylation is due to mutations in the gene encoding phosphomannomutase2 (PMM2-CDG). For this disease, which is autosomal and recessive, there is no cure at present. Most patients are composite heterozygous and carry one allele encoding an inactive mutant, R141H, and one encoding a hypomorphic mutant. Phosphomannomutase2 is a dimer. We reproduced composite heterozygosity in vitro by mixing R141H either with the wild type protein or the most common hypomorphic mutant F119L and compared the quaternary structure, the activity and the stability of the heterodimeric enzymes. We demonstrated that the activity of R141H/F119L heterodimers in vitro, which reproduces t…
PARTIAL SEQUENCING OF THE BETA-GLUCOSIDASE-ENCODING GENE FROM YEAST STRAINS ISOLATED FROM MUSTS AND WINES
2008
The aim of the present work was the identification of the gene encoding for β-glucosidase and its partial sequencing in the strainsPichia anomala AL112,Hanseniaspora uvarum Y8 andSaccharomyces cerevisiae AL41. To this aim degenerated primers, designed on the basis of aminoacid similarities of four known yeast β-glucosidases, have been used in PCR amplifications. An expected fragment of about 200 bp was amplified from all the DNAs, cloned and sequenced. Sequence homology demonstrated for the first time the presence of a β-glucosidase encoding gene inHanseniaspora uvarum andSaccharomyces cerevisiae.
Isolation of theMNN9gene ofYarrowia lipolytica(YlMNN9) and phenotype analysis of a mutantylmnn9Δ strain
2003
In this work we describe the isolation of the Yarrowia lipolytica homologue of Saccharomyces cerevisiae MNN9 gene, which we have named YlMNN9, and the phenotype analysis of a Y. lipolytica strain containing the disrupted YlMNN9 allele. YlMNN9 was cloned using degenerate consensus oligonucleotides to generate specific probes that were in turn used to screen mini-gene libraries. The gene is defined by a 1014 bp ORF predicted to encode a protein 337 amino acids long that shares significant homology with the Mnn9ps of S. cerevisiae, Candida albicans and Hansenula polymorpha, including a putative N-terminal transmembrane domain. Disruption of YlMNN9 leads to phenotypes such as resistance to sodi…