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Hannover, Germany

Schulz E.C.,University of Gottingen | Neumann P.,University of Gottingen | Gerardy-Schahn R.,Institute For Zellulare Chemie | Sheldrick G.M.,University of Gottingen | Ficner R.,University of Gottingen
Acta Crystallographica Section D: Biological Crystallography | Year: 2010

Endosialidase NF (endoNF) is a bacteriophage-derived endosialidase that specifically degrades α-2,8-linked polysialic acid. The structure of a new crystal form of endoNF in complex with sialic acid has been refined at 0.98 Å resolution. The 210 kDa homotrimeric multi-domain enzyme displays outstanding stability and resistance to SDS. Even at atomic resolution, only a minor fraction of side chains possess alternative conformations. However, multiple conformations of an active-site residue imply that it has an important catalytic function in the cleavage mechanism of polysialic acid. © 2010 International Union of Crystallography Printed in Singapore - all rights reserved.

Hadley B.,Griffith University | Maggioni A.,Griffith University | Ashikov A.,Institute For Zellulare Chemie | Ashikov A.,Radboud University Nijmegen | And 3 more authors.
Computational and Structural Biotechnology Journal | Year: 2014

The proteomes of eukaryotes, bacteria and archaea are highly diverse due, in part, to the complex post-translational modification of protein glycosylation. The diversity of glycosylation in eukaryotes is reliant on nucleotide sugar transporters to translocate specific nucleotide sugars that are synthesised in the cytosol and nucleus, into the endoplasmic reticulum and Golgi apparatus where glycosylation reactions occur. Thirty years of research utilising multidisciplinary approaches has contributed to our current understanding of NST function and structure. In this review, the structure and function, with reference to various disease states, of several NSTs including the UDP-galactose, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine, GDP-fucose, UDP-N-acetylglucosamine/UDP-glucose/GDP-mannose and CMP-sialic acid transporters will be described. Little is known regarding the exact structure of NSTs due to difficulties associated with crystallising membrane proteins. To date, no three-dimensional structure of any NST has been elucidated. What is known is based on computer predictions, mutagenesis experiments, epitope-tagging studies, in-vitro assays and phylogenetic analysis. In this regard the best-characterised NST to date is the CMP-sialic acid transporter (CST). Therefore in this review we will provide the current state-of-play with respect to the structure-function relationship of the (CST). In particular we have summarised work performed by a number groups detailing the affect of various mutations on CST transport activity, efficiency, and substrate specificity. © 2014 Hadley et al.

Maggioni A.,Griffith University | von Itzstein M.,Griffith University | Rodriguez Guzman I.B.,Griffith University | Ashikov A.,Institute For Zellulare Chemie | And 3 more authors.
ChemBioChem | Year: 2013

CMP-sialic acid transporter: We report an in-depth, multidisciplinary, structural study that has identified the amino acid residues intimately involved in CMP-sialic acid transporter (CST) substrate specificity. Our data provide a significant contribution towards a better understanding the structure-function relationship of this important family of transporters and the rational design of CST inhibitors. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keys T.G.,Institute For Zellulare Chemie | Gerardy-Schahn R.,Institute For Zellulare Chemie
BioSpektrum | Year: 2015

Polysaccharides are abundant extracellular matrix components and ideal materials for next-generation bioprostheses. Because the chain length critically impacts polymer properties, biotechnological production requires enzymes that allow polymer length control. For the capsule polymerase from Neisseria meningitidis serogroup B, we describe here the switching from processive to distributive polymer elongation. Our methodology delivered a finely tuned enzyme with narrow product distribution even in the absence of advanced high throughput screening platforms. © 2015, Springer-Verlag Berlin Heidelberg.

Rey-Gallardo A.,CSIC - Biological Research Center | Delgado-Martin C.,CSIC - Biological Research Center | Gerardy-Schahn R.,Institute For Zellulare Chemie | Rodriguez-Fernandez J.L.,CSIC - Biological Research Center | Vega M.A.,CSIC - Biological Research Center
Glycobiology | Year: 2011

Migration of mature dendritic cells (mDCs) to secondary lymphoid organs is required for the development of immunity. Recently, we reported that polysialic acid (PSA) and the transmembrane glycoprotein neuropilin-2 (NRP2) control mDC chemotaxis to CCL21 and that this process is dependent on the C-terminal basic region of the chemokine. Herein, we provide further insight into the molecular components controlling PSA regulated chemotaxis in mDCs. In the present study, we demonstrate that human mDCs express the NRP2 isoforms NRP2a and NRP2b, that both of them are susceptible to polysialylation and that polysialylation is required to specifically enhance chemotaxis toward CCL21 in mDCs. The results presented suggest that PSA attached to NRP2 isoforms acts as a binding module for the CCL21 chemokine, thereby facilitating its presentation to the chemokine receptor CCR7. To investigate the relevance of polysialylation on mDC migration, a xenograft mouse model was used and the migration of human DCs to mouse lymph nodes analyzed. Here, we demonstrate that the depletion of PSA from mDCs results in a drastic reduction in the migration of the cells to draining popliteal lymph nodes. With this finding, we provide first evidence that PSA is a crucial factor for in vivo migration of mDCs to lymph nodes. © 2010 The Author.

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