Institute For Zellulare Chemie

Hannover, Germany

Institute For Zellulare Chemie

Hannover, Germany
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Albuquerque A.,New University of Lisbon | Albuquerque A.,Institute For Zellulare Chemie | Campino L.,New University of Lisbon | Campino L.,FARO | And 2 more authors.
Parasites and Vectors | Year: 2017

Background: Canine leishmaniasis, a zoonotic disease caused by Leishmania infantum vectored by phlebotomine sand flies, is considered a relevant veterinary and public health problem in various countries, namely in the Mediterranean basin and Brazil, where dogs are considered the main reservoir hosts. Not only diseased dogs but also those subclinically infected play a relevant role in the transmission of L. infantum to vectors; therefore, early diagnosis is essential, under both a clinical and an epidemiological perspective. Molecular tools can be a more accurate and sensitive approach for diagnosis, with a wide range of protocols currently in use. The aim of the present report was to compare four PCR based protocols for the diagnosis of canine Leishmania infection in a cohort of dogs from the Douro region, Portugal. Results: A total of 229 bone marrow samples were collected from dogs living in the Douro region, an endemic region for leishmaniasis. Four PCR protocols were evaluated for Leishmania DNA detection in canine samples, three single (ITS1-PCR, MC-PCR and Uni21/Lmj4-PCR) and one nested (nested SSU rRNA-PCR). Two of the protocols were based on nuclear targets and the other two on kinetoplastid targets. The higher overall percentage of infected dogs was detected with the nested SSU rRNA-PCR (37.6%), which also was able to detect Leishmania DNA in a higher number of samples from apparently healthy dogs (25.3%). The ITS1-PCR presented the lowest level of Leishmania detection. Conclusions: Nested SSU rRNA-PCR is an appropriate method to detect Leishmania infection in dogs. Accurate and early diagnosis in clinically suspect as well as apparently healthy dogs is essential, in order to treat and protect animals and public health and contribute to the control and awareness of the disease. © 2017 The Author(s).

Schulz E.C.,University of Gottingen | Schwarzer D.,Institute For Zellulare Chemie | Frank M.,German Cancer Research Center | Stummeyer K.,Institute For Zellulare Chemie | And 4 more authors.
Journal of Molecular Biology | Year: 2010

An α-2,8-linked polysialic acid (polySia) capsule confers immune tolerance to neuroinvasive, pathogenic prokaryotes such as Escherichia coli K1 and Neisseria meningitidis and supports host infection by means of molecular mimicry. Bacteriophages of the K1 family, infecting E. coli K1, specifically recognize and degrade this polySia capsule utilizing tailspike endosialidases. While the crystal structure for the catalytic domain of the endosialidase of bacteriophage K1F (endoNF) has been solved, there is yet no structural information on the mode of polySia binding and cleavage available. The crystal structure of activity deficient active-site mutants of the homotrimeric endoNF cocrystallized with oligomeric sialic acid identified three independent polySia binding sites in each endoNF monomer. The bound oligomeric sialic acid displays distinct conformations at each site. In the active site, a Sia3 molecule is bound in an extended conformation representing the enzyme-product complex. Structural and biochemical data supported by molecular modeling enable to propose a reaction mechanism for polySia cleavage by endoNF. © 2010 Elsevier Ltd. All rights reserved.

Wolf S.,University of Hamburg | Warnecke S.,University of Hamburg | Ehrit J.,Institute For Zellulare Chemie | Freiberger F.,Institute For Zellulare Chemie | And 2 more authors.
ChemBioChem | Year: 2012

The cycloSal approach has been used in the past for the synthesis of a range of phosphorylated bioconjugates. In those reports, cycloSal nucleotides were allowed to react with different phosphate nucleophiles. With glycopyranosyl phosphates as nucleophiles, diphosphate-linked sugar nucleotides were formed. Here, cycloSal-nucleotides were used to prepare monophosphate-linked sugar nucleotides successfully in high anomeric purity and high chemical yield. The method was successfully used for the synthesis of three nucleotide glycopyranoses as model compounds. The method was then applied to the syntheses of CMP-N-acetyl-neuraminic acids (CMP-Neu5NAc) and of four derivatives with different modifications at their amino functions (N-propanoyl, N-butanoyl, N-pentanoyl and N-cyclopropylcarbonyl). The compounds were used for initial enzymatic studies with a bacterial polysialyltransferase (polyST). Surprisingly, the enzyme showed marked differences in terms of utilisation of the four derivatives. The N-propanoyl, N-butanoyl, and N-pentanoyl derivatives were efficiently used in a first transfer with a fluorescently labelled trisialo-acceptor. However, elongation of the resulting tetrasialo-acceptors worsened progressively with the size of the N-acyl chain. The N-pentanoyl derivative allowed a single transfer, leading to a capped tetramer. The N-cyclopropylcarbonyl derivative was not transferred. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Bohm R.,Griffith University | Freiberger F.,Institute For Zellulare Chemie | Stummeyer K.,Institute For Zellulare Chemie | Gerardy-Schahn R.,Institute For Zellulare Chemie | And 2 more authors.
ChemBioChem | Year: 2010

On the loose: We report an STD NMR spectroscopic study of the polysialyltransferase from Neisseria meningitidis serogroup B (NmB-polyST). The spectra reveal that the cytosine and ribose moiety receive more saturation than the sialic acid residue of CMPNeu5Ac. This loose binding enables a fast and efficient sialyl transfer to the acceptor substrate. Our analysis offers a view of the structural determinants necessary for binding to NmB-polyST that provide the basis for the development of novel NmB-polyST inhibitors. (Figure Presented). © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Schulz E.C.,University of Gottingen | Bergfeld A.K.,Institute For Zellulare Chemie | Bergfeld A.K.,University of California at San Diego | Ficner R.,University of Gottingen | Muhlenhoff M.,Institute For Zellulare Chemie
PLoS ONE | Year: 2011

The major virulence factor of the neuroinvasive pathogen Escherichia coli K1 is the K1 capsule composed of α2,8-linked polysialic acid (polySia). K1 strains harboring the CUS-3 prophage modify their capsular polysaccharide by phase-variable O-acetlyation, a step that is associated with increased virulence. Here we present the crystal structure of the prophage-encoded polysialate O-acetyltransferase NeuO. The homotrimeric enzyme belongs to the left-handed β-helix (LβH) family of acyltransferases and is characterized by an unusual funnel-shaped outline. Comparison with other members of the LβH family allowed the identification of active site residues and proposal of a catalytic mechanism and highlighted structural characteristics of polySia specific O-acetyltransferases. As a unique feature of NeuO, the enzymatic activity linearly increases with the length of the N-terminal poly-ψ-domain which is composed of a variable number of tandem copies of an RLKTQDS heptad. Since the poly-ψ-domain was not resolved in the crystal structure it is assumed to be unfolded in the apo-enyzme. © 2011 Schulz 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.

Schulz E.C.,University of Gottingen | Dickmanns A.,University of Gottingen | Urlaub H.,Max Planck Institute for Chemistry | Schmitt A.,University of Gottingen | And 5 more authors.
Nature Structural and Molecular Biology | Year: 2010

Protein folding is often mediated by molecular chaperones. Recently, a novel class of intramolecular chaperones has been identified in tailspike proteins of evolutionarily distant viruses, which require a C-terminal chaperone for correct folding. The highly homologous chaperone domains are interchangeable between pre-proteins and release themselves after protein folding. Here we report the crystal structures of two intramolecular chaperone domains in either the released or the pre-cleaved form, revealing the role of the chaperone domain in the formation of a triple-Β-helix fold. Tentacle-like protrusions enclose the polypeptide chains of the pre-protein during the folding process. After the assembly, a sensory mechanism for correctly folded Β-helices triggers a serine-lysine catalytic dyad to autoproteolytically release the mature protein. Sequence analysis shows a conservation of the intramolecular chaperones in functionally unrelated proteins sharing Β-helices as a common structural motif. © 2010 Nature America, Inc. All rights reserved.

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.

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.

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