In silico Investigation of the PglB Active Site Reveals Transient Catalytic States and Octahedral Metal Ion Coordination
The last step of the bacterial N-glycosylation pathway involves PglB, an oligosaccharyltransferase, which is responsible for the en bloc transfer of a fully assembled oligosaccharide chain to a protein possessing the extended motif D/E-X-N-X-S/T. Recently, this molecule had its full structure elucidated, enabling the description of its domains and the proposition of a catalytic mechanism. By employing molecular dynamics simulations, we were able to evaluate structural aspects of PglB, suggesting prevalent motions that may bring insights into the mechanism of the glycosylated peptide detachment. Additionally, we identified ...
Source: Glycobiology - October 6, 2015 Category: Biology Authors: Pedebos, C., Arantes, P. R., Giesel, G. M., Verli, H. Tags: Computational Biology Source Type: research
A novel monoclonal antibody to a defined peptide epitope in MUC16
The MUC16 mucin is overexpressed and aberrantly glycosylated in ovarian carcinomas. Immunodetection of circulating MUC16 is one of the most used cancer biomarker assays, but existing antibodies to MUC16 fail to distinguish normal and aberrant cancer glycoforms. Although all antibodies react with the tandem-repeat region, their epitopes appear to be conformational dependent and not definable by a short peptide. Aberrant glycoforms of MUC16 may constitute promising targets for diagnostic and immunotherapeutic intervention, and it is important to develop well-defined immunogens for induction of potent MUC16 immunity. Here, we...
Source: Glycobiology - October 6, 2015 Category: Biology Authors: Marcos-Silva, L., Ricardo, S., Chen, K., Blixt, O., Arigi, E., Pereira, D., Hogdall, E., Mandel, U., Bennett, E. P., Vakhrushev, S. Y., David, L., Clausen, H. Tags: Cancer Biology Source Type: research
A glycomic approach reveals a new mycobacterial polysaccharide
Mycobacterium tuberculosis lipoarabinomannan (LAM) and biosynthetically related lipoglycans and glycans play an important role in host–pathogen interactions. Therefore, the elucidation of the complete biosynthetic pathways of these important molecules is expected to afford novel therapeutic targets. The characterization of biosynthetic enzymes and transporters involved in the formation and localization of these complex macromolecules in the bacterial cell envelope largely relies on genetic manipulation of mycobacteria and subsequent analyses of lipoglycan structural alterations. However, lipoglycans are present in re...
Source: Glycobiology - October 6, 2015 Category: Biology Authors: Larrouy-Maumus, G., Gilleron, M., Skovierova, H., Zuberogoitia, S., Brennan, P. J., Puzo, G., Jackson, M., Nigou, J. Tags: Analytical Glycobiology Source Type: research
Identification of the S-layer glycoproteins and their covalently linked glycans in the halophilic archaeon Haloarcula hispanica
In this study, the S-layer proteins of Har. hispanica were extracted and characterized. The S-layer was found containing two different glycoproteins which shared highly similar amino acid sequences. The genes coding for these two S-layer glycoproteins were found next to each other in the genome. Moreover, the N- and O-linked glycans were released from these two S-layer glycoproteins for structural determination. Based on the mass spectrometry and nuclear magnetic resonance, the N-glycan was determined as a branched trisaccharide containing a 225 Da residue corresponded to a 2-amino-6-sulfo-2, 6-dideoxy-quinovose, which was...
Source: Glycobiology - October 6, 2015 Category: Biology Authors: Lu, H., Lu, Y., Ren, J., Wang, Z., Wang, Q., Luo, Y., Han, J., Xiang, H., Du, Y., Jin, C. Tags: Analytical Glycobiology Source Type: research
The trans-sialidase, the major Trypanosoma cruzi virulence factor: Three decades of studies
Chagas’ disease is a potentially life-threatening disease caused by the protozoan parasite Trypanosoma cruzi. Since the description of Chagas'disease in 1909 extensive research has identified important events in the disease in order to understand the biochemical mechanism that modulates T. cruzi-host cell interactions and the ability of the parasite to ensure its survival in the infected host. Exactly 30 years ago, we presented evidence for the first time of a trans-sialidase activity in T. cruzi (T. cruzi-TS). This enzyme transfers sialic acid from the host glycoconjugates to the terminal β-galactopyranosyl res...
Source: Glycobiology - October 6, 2015 Category: Biology Authors: Freire-de-Lima, L., Fonseca, L., Oeltmann, T., Mendonca-Previato, L., Previato, J. Tags: REVIEW Source Type: research
Remembering J. A. Cifonelli (1916-2005) An Early Leader in Glycosaminoglycan Biochemistry
(Source: Glycobiology)
Source: Glycobiology - October 6, 2015 Category: Biology Authors: Fishkin, C. A. Tags: GLYCO-FORUM Source Type: research
The 2015 Karl Meyer Lectureship Award and the Rosalind Kornfeld Award for Lifetime Achievement in Glycobiology, from the Society for Glycobiology
(Source: Glycobiology)
Source: Glycobiology - October 6, 2015 Category: Biology Authors: West, C. M. Tags: GLYCO-FORUM Source Type: research
Meeting and Course Announcements
(Source: Glycobiology)
Source: Glycobiology - October 6, 2015 Category: Biology Tags: GLYCO-FORUM Source Type: research
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(Source: Glycobiology)
Source: Glycobiology - October 6, 2015 Category: Biology Tags: Cover/Standing Material Source Type: research
Editorial Board
(Source: Glycobiology)
Source: Glycobiology - October 6, 2015 Category: Biology Tags: Cover/Standing Material Source Type: research
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(Source: Glycobiology)
Source: Glycobiology - October 6, 2015 Category: Biology Tags: Cover/Standing Material Source Type: research
Structural glycobiology of human {alpha}1-acid glycoprotein and its implications for pharmacokinetics and inflammation
Human α1-acid glycoprotein (AGP) is an abundant human plasma glycoprotein that may be N-glycosylated at five positions. AGP plays important roles on pharmacokinetics and can rise up to 5-fold in inflammatory events. In such events, the glycan chains attached to Asn54, Asn75 and Asn85 may become fucosylated, originating a sialyl-Lewis X epitope. This epitope, in turn, can bind selectin proteins. Such interplay is important for immunomodulation. While the X-ray structure of unglycosylated AGP has been reported, the absence of the glycan chains hampered the further insights into its structural biology and, ultimately, i...
Source: Glycobiology - August 27, 2015 Category: Biology Authors: Fernandes, C. L., Ligabue-Braun, R., Verli, H. Tags: Structural Biology Source Type: research
Protective effects of polysialic acid on proteolytic cleavage of FGF2 and proBDNF/BDNF
Polysialic acid (polySia) is a linear polymer of sialic acid that modifies neural cell adhesion molecule (NCAM) in the vertebrate brain. PolySia is a large and exclusive molecule that functions as a negative regulator of cell–cell interactions. Recently, we demonstrated that polySia can specifically bind fibroblast growth factor 2 (FGF2) and BDNF; however, the protective effects of polySia on the proteolytic cleavage of these proteins remain unknown, although heparin/heparan sulfate has been shown to impair the cleavage of FGF2 by trypsin. Here, we analyzed the protective effects of polySia on the proteolytic cleavag...
Source: Glycobiology - August 27, 2015 Category: Biology Authors: Hane, M., Matsuoka, S., Ono, S., Miyata, S., Kitajima, K., Sato, C. Tags: Glycan Recognition Source Type: research
Cello-oligomer-binding dynamics and directionality in family 4 carbohydrate-binding modules
Carbohydrate-binding modules (CBMs) play significant roles in modulating the function of cellulases, and understanding the protein–carbohydrate recognition mechanisms by which CBMs selectively bind substrate is critical to development of enhanced biomass conversion technology. CBMs exhibit a limited range of specificity and appear to bind polysaccharides in a directional fashion dictated by the position of the ring oxygen relative to the protein fold. The two family 4 CBMs of Cellulomonas fimi Cel9B (CfCBM4) are reported to preferentially bind cellulosic substrates. However, experimental evidence suggests that these ...
Source: Glycobiology - August 27, 2015 Category: Biology Authors: Kognole, A. A., Payne, C. M. Tags: Glycan Recognition Source Type: research
Cooperative role of calnexin and TigA in Aspergillus oryzae glycoprotein folding
In this study, we found that a protein disulfide isomerase homolog TigA can bind with A. oryzae CNX (AoCNX), which was revealed to specifically recognize monoglucosylated glycans, similarly to CNX derived from other species, and accelerate the folding of G1M9GN2-ribonuclease (RNase) in vitro. For refolding experiments, a homogeneous monoglucosylated high-mannose-type glycoprotein G1M9GN2-RNase was chemoenzymatically synthesized from G1M9GN-oxazoline and GN-RNase. Denatured G1M9GN2-RNase was refolded with highest efficiency in the presence of both soluble form of AoCNX and TigA. TigA contains two thioredoxin domains with CG...
Source: Glycobiology - August 27, 2015 Category: Biology Authors: Wang, N., Seko, A., Takeda, Y., Kikuma, T., Ito, Y. Tags: Glycan Recognition Source Type: research
