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https://www.readbyqxmd.com/read/28821844/n-glycosylation-triggers-a-dual-selection-pressure-in-eukaryotic-secretory-proteins
#1
Máximo Lopez Medus, Gabriela E Gomez, Lucía F Zacchi, Paula M Couto, Carlos A Labriola, María S Labanda, Rodrigo Corti Bielsa, Eugenia M Clérico, Benjamin L Schulz, Julio J Caramelo
Nearly one third of the eukaryotic proteome traverses the secretory pathway and most of these proteins are N-glycosylated in the lumen of the endoplasmic reticulum. N-glycans fulfill multiple structural and biological functions, and are crucial for productive folding of many glycoproteins. N-glycosylation involves the attachment of an oligosaccharide to selected asparagine residues in the sequence N-X-S/T (X ≠ P), a motif known as an N-glycosylation'sequon'. Mutations that create novel sequons can cause disease due to the destabilizing effect of a bulky N-glycan...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28820257/residues-comprising-the-enhanced-aromatic-sequon-influence-protein-n-glycosylation-efficiency
#2
Yen-Wen Huang, Hwai-I Yang, Ying-Ta Wu, Tsui-Ling Hsu, Tzu-Wen Lin, Jeffery W Kelly, Chi-Huey Wong
N-glycosylation is an important co- and/or post-translational modification that occurs on the vast majority of the 1/3 of the mammalian proteome that traverses the cellular secretory pathway, regulating glycoprotein folding and functions. Previous studies on the sequence requirements for N-glycosylation have yielded the Asn-X-Ser/Thr (NXS/T) sequon and the enhanced aromatic sequons (Phe-X-Asn-X-Thr and Phe-X-X-Asn-X-Thr) which can be efficiently N-glycosylated. To further investigate the influence of sequence variation on N-glycosylation efficiency in the context of a 5-residue enhanced aromatic sequon, we used the human CD2 adhesion domain (hCD2ad) to screen the i-2, i-1, i+1 and i+2 residues flanking Asn at the i position...
August 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28820060/peptide-specificity-analysis-of-peptide-n-glycanases-using-synthetic-chitobiose-pentapeptides
#3
Taiki Kuribara, Toshihiro Ishihara, Takaya Kudo, Makoto Hirano, Kiichiro Totani
Peptide:N-glycanase is a deglycosylation enzyme releasing N-glycan from glycoproteins. Although glycan specificity analysis of this enzyme has been reported, recognition requirements for the peptide sequence have not been precisely elucidated. Therefore, in this study, we carried out peptide specificity analysis of several peptide:N-glycanases. Using synthetic chitobiose-pentapeptide substrates having a systematic series of amino acid sequences composed of hydrophobic leucine and hydrophilic serine, we examined the peptide specificities of peptide:N-glycanases comprising yeast cytoplasmic PNGase, bacterial PNGase F, and plant PNGase A by ultra-performance liquid chromatography combined with electrospray ionization mass spectrometry...
August 18, 2017: Protein and Peptide Letters
https://www.readbyqxmd.com/read/28819389/discovery-of-non-invasive-glycan-biomarkers-for-detection-and-surveillance-of-gastric-cancer
#4
Ruihuan Qin, Junjie Zhao, Wenjun Qin, Zejian Zhang, Ran Zhao, Jing Han, Yupeng Yang, Lixiao Li, Xuefei Wang, Shifang Ren, Yihong Sun, Jianxin Gu
Purpose: Gastric cancer (GC), one of the world's top five most common cancers, is the third leading cause of cancer related death. It is urgent to identify non-invasive biomarkers for GC. The objective of our study was to find out non-invasive biomarkers for early detection and surveillance of GC based on glycomic analysis. Method: Ethyl esterification derivatization combined with MALDI-TOF MS analysis was employed for the comprehensive serum glycomic analysis in order to investigate glycan markers that would indicate the onset and progression of gastric cancer...
2017: Journal of Cancer
https://www.readbyqxmd.com/read/28818650/recombinant-vs-native-anisakis-haemoglobin-ani-s-13-its-appraisal-as-a-new-gold-standard-for-the-diagnosis-of-allergy
#5
Juan González-Fernández, Luis Rivas, Juan Román Luque-Ortega, Rafael Núñez-Ramírez, Pamela Campioli, Teresa Gárate, María J Perteguer, Alvaro Daschner, Carmen Cuéllar
Recombinant allergens are currently the best option for serodiagnosis of human anisakiasis in terms of sensitivity and specificity. However, previous reports showed high rates of anisakiasis patients who were negative to Ani s 7 and especially to Ani s 1. Recently, Anisakis haemoglobin was described as a major allergen (Ani s 13). Although Ani s 13 belongs to a conserved protein family, it seems not to be a cross-reacting antigen because of the absence of IgE recognition against Ascaris haemoglobin in Anisakis patients...
August 14, 2017: Experimental Parasitology
https://www.readbyqxmd.com/read/28817611/the-directed-migration-of-gonadal-distal-tip-cells-in-caenorhabditis-elegans-requires-ngat-1-a-%C3%A3-1-4-n-acetylgalactosaminyltransferase-enzyme
#6
Joseph Veyhl, Robert J Dunn, Wendy L Johnston, Alexa Bennett, Lijia W Zhang, James W Dennis, Harry Schachter, Joseph G Culotti
Glycoproteins such as growth factor receptors and extracellular matrix have well-known functions in development and cancer progression, however, the glycans at sites of modification are often heterogeneous molecular populations which makes their functional characterization challenging. Here we provide evidence for a specific, discrete, well-defined glycan modification and regulation of a stage-specific cell migration in Caenorhabditis elegans. We show that a chain-terminating, putative null mutation in the gene encoding a predicted β1,4-N-acetylgalactosaminyltransferase, named ngat-1, causes a maternally rescued temperature sensitive (ts) defect in the second phase of the three phase migration pattern of the posterior, but not the anterior, hermaphrodite Distal Tip Cell (DTC)...
2017: PloS One
https://www.readbyqxmd.com/read/28816453/modeling-of-oligosaccharides-within-glycoproteins-from-free-energy-landscapes
#7
Aysegül Turupcu, Chris Oostenbrink
In spite of the abundance of glycoproteins in biological processes, relatively little three-dimensional structural data is available for glycan structures. Here, we study the structure and flexibility of the vast majority of mammalian oligosaccharides appearing in N- and O- glycosylated proteins using a bottom up approach. We report the conformational free-energy landscapes of all relevant glycosidic linkages as obtained from local elevation simulations and subsequent umbrella sampling. To the best of our knowledge, this represents the first complete conformational library for the construction of N- and O-glycan structures...
August 17, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28814130/identification-and-characterization-of-a-sulfoglycosidase-from-bifidobacterium-bifidum-implicated-in-mucin-glycan-utilization
#8
Toshihiko Katoh, Takako Maeshibu, Kei-Ichi Kikkawa, Aina Gotoh, Yusuke Tomabechi, Motoharu Nakamura, Wei-Hsiang Liao, Masanori Yamaguchi, Hisashi Ashida, Kenji Yamamoto, Takane Katayama
Human gut symbiont bifidobacteria possess carbohydrate-degrading enzymes that act on the O-linked glycans of intestinal mucins to utilize those carbohydrates as carbon sources. However, our knowledge about mucin type O-glycan degradation by bifidobacteria remains fragmentary, especially regarding how they decompose sulfated glycans, which are abundantly found in mucin sugar-chains. Here, we examined the abilities of several Bifidobacterium strains to degrade a sulfated glycan substrate and identified a 6-sulfo-β-d-N-acetylglucosaminidase, also termed sulfoglycosidase, encoded by bbhII from Bifidobacterium bifidum JCM 7004...
August 17, 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/28813678/therapeutic-antibodies-to-ganglioside-gd2-evolved-from-highly-selective-germline-antibodies
#9
Eric Sterner, Megan L Peach, Marc C Nicklaus, Jeffrey C Gildersleeve
Antibodies play a crucial role in host defense and are indispensable research tools, diagnostics, and therapeutics. Antibody generation involves binding of genomically encoded germline antibodies followed by somatic hypermutation and in vivo selection to obtain antibodies with high affinity and selectivity. Understanding this process is critical for developing monoclonal antibodies, designing effective vaccines, and understanding autoantibody formation. Prior studies have found that antibodies to haptens, peptides, and proteins evolve from polyspecific germline antibodies...
August 15, 2017: Cell Reports
https://www.readbyqxmd.com/read/28813656/fc%C3%AE-receptor-function-and-the-design-of-vaccination-strategies
#10
REVIEW
Stylianos Bournazos, Jeffrey V Ravetch
Through specific interactions with distinct types of Fcγ receptors (FcγRs), the Fc domain of immunoglobulin G (IgG) mediates a wide spectrum of immunological functions that influence both innate and adaptive responses. Recent studies indicate that IgG Fc-FcγR interactions are dynamically regulated during an immune response through the control of the Fc-associated glycan structure and Ig subclass composition on the one hand and selective FcγR expression on immune cells on the other, which together determine the capacity of IgG to interact in a cell-type-specific manner with specific members of the FcγR family...
August 15, 2017: Immunity
https://www.readbyqxmd.com/read/28813016/a-novel-high-mannose-specific-lectin-from-the-green-alga-halimeda-renschii-exhibits-a-potent-anti-influenza-virus-activity-through-high-affinity-binding-to-the-viral-hemagglutinin
#11
Jinmin Mu, Makoto Hirayama, Yuichiro Sato, Kinjiro Morimoto, Kanji Hori
We have isolated a novel lectin, named HRL40 from the green alga Halimeda renschii. In hemagglutination-inhibition test and oligosaccharide-binding experiment with 29 pyridylaminated oligosaccharides, HRL40 exhibited a strict binding specificity for high-mannose N-glycans having an exposed (α1-3) mannose residue in the D2 arm of branched mannosides, and did not have an affinity for monosaccharides and other oligosaccharides examined, including complex N-glycans, an N-glycan core pentasaccharide, and oligosaccharides from glycolipids...
August 16, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28810664/bacterial-phosphoglycosyl-transferases-initiators-of-glycan-biosynthesis-at-the-membrane-interface
#12
Vinita Lukose, Marthe T C Walvoort, Barbara Imperiali
Phosphoglycosyl transferases (PGTs) initiate the biosynthesis of both essential and virulence-associated bacterial glycoconjugates including lipopolysaccharide, peptidoglycan and glycoproteins. PGTs catalyze the transfer of a phosphosugar moiety from a nucleoside diphosphate sugar to a polyprenol phosphate, to form a membrane-bound polyprenol diphosphosugar product. PGTs are integral membrane proteins, which include between 1 and 11 predicted transmembrane domains. Despite this variation, common motifs have been identified in PGT families through bioinformatics and mutagenesis studies...
September 1, 2017: Glycobiology
https://www.readbyqxmd.com/read/28810662/galectin-9-binds-to-o-glycans-on-protein-disulfide-isomerase
#13
Katrin Schaefer, Nicholas E Webb, Mabel Pang, Jenny E Hernandez-Davies, Katharine P Lee, Pascual Gonzalez, Martin V Douglass, Benhur Lee, Linda G Baum
Changes in the T cell surface redox environment regulate critical cell functions, such as cell migration, viral entry and cytokine production. Cell surface protein disulfide isomerase (PDI) contributes to the regulation of T cell surface redox status. Cell surface PDI can be released into the extracellular milieu or can be internalized by T cells. We have found that galectin-9, a soluble lectin expressed by T cells, endothelial cells and dendritic cells, binds to and retains PDI on the cell surface. While endogenous galectin-9 is not required for basal cell surface PDI expression, exogenous galectin-9 mediated retention of cell surface PDI shifted the disulfide/thiol equilibrium on the T cell surface...
September 1, 2017: Glycobiology
https://www.readbyqxmd.com/read/28810661/identification-of-lectin-counter-receptors-on-cell-membranes-by-proximity-labeling
#14
Gang Wu, Manjula Nagala, Paul R Crocker
Lectin-glycan interactions play important roles in many biological systems, but the nature of glycoprotein counter-receptors expressed on cell membranes is often poorly understood. To help overcome this problem, we developed a method based on proximity labeling technology. Using a peroxidase-coupled lectin, addition of H2O2 and tyramide-biotin substrates leads to generation of short-range biotin radicals that biotinylate proteins in the immediate vicinity of the bound lectin, which can subsequently be identified...
September 1, 2017: Glycobiology
https://www.readbyqxmd.com/read/28809486/assembling-glycan-charged-dolichol-phosphates-chemoenzymatic-synthesis-of-a-haloferax-volcanii-n-glycosylation-pathway-intermediate
#15
Yifat Elharar, Ananda R Podilapu, Ziqiang Guan, Suvarn S Kulkarni, Jerry Eichler
N-glycosylation, the covalent attachment of glycans to select protein target Asn residues, is a post-translational modification performed by all three domains of life. In the halophilic archaea Haloferax volcanii, where understanding of this universal protein-processing event is relatively well-advanced, genes encoding the components of the Agl (archaeal glycosylation) pathway responsible for the assembly and attachment of an N-linked pentasaccharide have been identified. As elsewhere, the N-linked glycan is assembled on phosphodolichol carriers before transfer to target Asn residues...
August 15, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28808998/microfluidics-mass-spectrometry-of-protein-carbohydrate-interactions-applications-to-the-development-of-therapeutics-and-biomarker-discovery
#16
Alina D Zamfir
The functional interactions of carbohydrates and their protein receptors are the basis of biological events critical to the evolution of pathological states. Hence, for the past years, such interactions have become the focus of research for the development of therapeutics and discovery of novel glycan biomarkers based on their binding affinity. Due to the high sensitivity, throughput, reproducibility, and capability to ionize minor species in heterogeneous mixtures, microfluidics-mass spectrometry (MS) has recently emerged as a method of choice in protein-glycan interactomics...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28808731/biomacromolecules-as-tools-and-objects-in-nanometrology-current-challenges-and-perspectives
#17
Payam Hashemi, Luise Luckau, Petra Mischnick, Sarah Schmidt, Rainer Stosch, Bettina Wünsch
Nucleic acids, proteins, and polysaccharides are the most important classes of biopolymers. The inherent properties of biomacromolecules are contrary to those of well-defined small molecules consequently raising a number of specific challenges which become particularly apparent if biomacromolecules are treated as objects in quantitative analysis. At the same time, their specific functional ability of molecular recognition and self-organization (e.g., enzymes, antibodies, DNA) enables us to make biomacromolecules serving as molecular tools in biochemistry and molecular biology, or as precisely controllable dimensional platforms for nanometrological applications...
August 14, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28808112/regulation-of-perforin-activation-and-pre-synaptic-toxicity-through-c-terminal-glycosylation
#18
Imran G House, Colin M House, Amelia J Brennan, Omer Gilan, Mark A Dawson, James C Whisstock, Ruby Hp Law, Joseph A Trapani, Ilia Voskoboinik
Perforin is a highly cytotoxic pore-forming protein essential for immune surveillance by cytotoxic lymphocytes. Prior to delivery to target cells by exocytosis, perforin is stored in acidic secretory granules where it remains functionally inert. However, how cytotoxic lymphocytes remain protected from their own perforin prior to its export to secretory granules, particularly in the Ca(2+)-rich endoplasmic reticulum, remains unknown. Here, we show that N-linked glycosylation of the perforin C-terminus at Asn549 within the endoplasmic reticulum inhibits oligomerisation of perforin monomers and thus protects the host cell from premature pore formation...
August 14, 2017: EMBO Reports
https://www.readbyqxmd.com/read/28803976/canavalia-bonariensis-lectin-molecular-bases-of-glycoconjugates-interaction-and-antiglioma-potential
#19
Benildo Sousa Cavada, Mayara Torquato Lima Silva, Vinicius Jose Silva Osterne, Vanir Reis Pinto-Junior, Ana Paula Machado do Nascimento, Ingrid Alessandra Victoria Wolin, Isabella Aparecida Heinrich, Clareane Avelino Simplicio Nobre, Cleane Gomes Moreira, Claudia Figueiredo Lossio, Cintia Renata Costa Rocha, Jorge Luiz Martins, Kyria Santiago Nascimento, Rodrigo Bainy Leal
CaBo is a mannose/glucose-specific lectin purified from seeds of Canavalia bonariensis. In the present work, we report the CaBo crystal structure determined to atomic resolution in the presence of X-man, a specific ligand. Similar to the structural characteristics of other legume lectins, CaBo presented the jellyroll motif, a metal binding site occupied by calcium and manganese ions close to the carbohydrate-recognition domain (CRD). In vitro test of CaBo cytotoxicity against glioma cells demonstrated its ability to decrease the cellular viability and migration by induction of autophagy and cell death...
August 10, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28803541/ion-exchange-chromatography-purification-of-extracellular-vesicles
#20
Maja Kosanović, Bojana Milutinović, Sanja Goč, Ninoslav Mitić, Miroslava Janković
Despite numerous studies, isolating pure preparations of extracellular vesicles (EVs) has proven challenging. Here, we compared ion-exchange chromatography (IEC) to the widely used sucrose density gradient (SDG) centrifugation method for the purification of EVs. EVs in bulk were isolated from pooled normal human amniotic fluid (AF) by differential centrifugation followed by IEC or sucrose density gradient separation. The purity of the isolated EVs was evaluated by electrophoresis and lectin blotting/immuno blotting to monitor the distribution of total proteins, different EVs markers, and selected N-glycans...
August 1, 2017: BioTechniques
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