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Christen E.H.,Albert Ludwigs University of Freiburg | Christen E.H.,ETH Zurich | Gubeli R.J.,Albert Ludwigs University of Freiburg | Kaufmann B.,Albert Ludwigs University of Freiburg | And 7 more authors.
Organic and Biomolecular Chemistry | Year: 2012

The Cu(i)-catalyzed cycloaddition of terminal azides and alkynes (click chemistry) represents a highly specific reaction for the functionalization of biomolecules with chemical moieties such as dyes or polymer matrices. In this study we evaluate the use of bicinchoninic acid (BCA) as a ligand for Cu(i) under physiological reaction conditions. We demonstrate that the BCA-Cu(i)-complex represents an efficient catalyst for the conjugation of fluorophores or biotin to alkyne- or azide-functionalized proteins resulting in increased or at least equal reaction yields compared to commonly used catalysts like Cu(i) in complex with TBTA (tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl] amine) or BPAA (bathophenanthroline disulfonic acid). The stabilization of Cu(i) with BCA represents a new strategy for achieving highly efficient bioconjugation reactions under physiological conditions in many application fields. © 2012 The Royal Society of Chemistry.


Acevedo-Rocha C.G.,Max-Planck-Institut für Kohlenforschung | Acevedo-Rocha C.G.,University of Marburg | Hoesl M.G.,TU Berlin | Nehring S.,TU Berlin | And 5 more authors.
Catalysis Science and Technology | Year: 2013

The incorporation of several non-canonical amino acids into the Thermoanaerobacter thermohydrosulfuricus lipase confers not only activity enhancement upon treatment with organic solvents (by up to 450%) and surfactants (resp. 1630%), but also protective effects against protein reducing (resp. 140%), alkylating (resp. 160%), and denaturing (resp.190%) agents as well as inhibitors (resp. 40%). This approach offers novel chemically diversified biocatalysts for hostile environments. © 2013 The Royal Society of Chemistry.


Ribitsch D.,ACIB | Acero E.H.,ACIB | Greimel K.,ACIB | Eiteljoerg I.,ACIB | And 6 more authors.
Biocatalysis and Biotransformation | Year: 2012

A new cutinase from Thermobifida alba (Tha-Cut1) was cloned and characterized for polyethylene terephthalate (PET) hydrolysis. Tha-Cut1 showed a high degree of identity to a T. cellulolysitica cutinase with only four amino acid differences outside the active site area, according to modeling data. Yet, Tha-Cut1 was more active in terms of PET surface hydrolysis leading to considerable improvement in hydrophilicity quantified based on a decrease of the water contact angle from 87.7° to 45.0°. The introduction of new carboxyl groups was confirmed and measured after esterification with the fluorescent reagent alkyl bromide, 2-(bromomethyl) naphthalene (BrNP), resulting in a fluorescence emission intensity increase from 980 to 1420 a.u. On the soluble model substrates p-nitrophenyl acetate (PNPA) and p-nitrophenyl butyrate (PNPB), the cutinase showed Km values of 213 and 1933 μM and kcat values of 2.72 and 6.03 s -1 respectively. The substrate specificity was investigated with bis(benzoyloxyethyl)terephthalate (3PET) and Tha-Cut1 was shown to release primarily 2-hydroxyethyl benzoate. This contrasts with the well-studied Humicula insolens cutinase which preferentially liberates terminal benzoic acid from 3PET. © 2012 Informa UK, Ltd.


Fliedl L.,ACIB | Kast F.,ACIB | Grillari J.,ACIB | Grillari J.,University of Natural Resources and Life Sciences, Vienna | And 3 more authors.
New Biotechnology | Year: 2015

Transient gene expression (TGE) is an essential tool for the production of recombinant proteins, especially in early drug discovery and development phases of biopharmaceuticals. The need for fast production of sufficient recombinant protein for initial tests has dramatically increased with increase in the identification of potential novel pharmaceutical targets. One of the critical factors for transient transfection is plasmid copy number (PCN), for which we here provide an optimized qPCR based protocol. Thereby, we show the loss of PCN during a typical batch process of HEK293 cells after transfection from 606,000 to 4560 copies per cell within 5 days. Finally two novel human kidney cell lines, RS and RPTEC/TERT1 were compared to HEK293 and proved competitive in terms of PCN and specific productivity. In conclusion, since trafficking and degradation of plasmid DNA is not fully understood yet, improved methods for analysis of PCN may contribute to design specific and more stable plasmids for high yield transient gene expression systems. © 2015 Elsevier B.V.


Krempl P.M.,ACIB | Krempl P.M.,University of Graz | Mairhofer J.,ACIB | Mairhofer J.,Institute of Applied Microbiology | And 4 more authors.
Bioinformatics | Year: 2012

We present a plug-in for Pathway Tools, an integrated systems biology software to create, maintain and query Pathway/Genome Databases. Fully integrated into the graphical user interface and menu, this plug-in extends the application's functionality by the ability to create multiple sequence alignments, systematically annotate insertion sequence (IS) elements and analyse their activity by cross-species comparison tools. Microarray probes can be automatically mapped to target genes, and expression data obtained with these arrays can be transformed into input formats needed to visualize them in the various omics viewers of Pathway Tools. The plug-in API itself allows developers to integrate their own functions into the Pathway Tools menu. © The Author 2012. Published by Oxford University Press. All rights reserved.


Fliedl L.,ACIB | Grillari J.,ACIB | Grillari J.,University of Natural Resources and Life Sciences, Vienna | Grillari-Voglauer R.,ACIB | Grillari-Voglauer R.,University of Natural Resources and Life Sciences, Vienna
New Biotechnology | Year: 2015

The market of recombinant proteins as human pharmaceuticals has surpassed annual revenues of more than 150 billion dollars. The marketed proteins are often complex in terms of post-translational modifications and conventional hosts have shown weaknesses in terms of quality of these recombinant proteins. Especially the non-human glycopatterns leading to immunogenicity or shortened in vivo half-life have gained attention over the past decade. Therefore, production cell lines with better or novel characteristics are required and human cell lines seem to be the most genuine and logical choice. Thus, several human cell lines have been used to generate biopharmaceuticals. We here present an overview of such examples and highlight their promise for biopharmaceutical production processes of the future. © 2014 Elsevier B.V.


Fliedl L.,ACIB | Manhart G.,ACIB | Kast F.,ACIB | Katinger H.,University of Natural Resources and Life Sciences, Vienna | And 5 more authors.
Journal of Biotechnology | Year: 2014

Human host cell lines for the production of biopharmaceutical proteins are of interest due to differences in the glycosylation patterns of human and animal cell lines. Specifically, sialylation, which has a major impact on half-life and immunogenicity of recombinant biopharmaceuticals, differs markedly. Here, we established and characterized an immortalized well documented and serum-free host cell line, RS, from primary human renal proximal tubular epithelial cells (RPTEC). In order to test its capacity to produce complex glycosylated proteins, stable recombinant human erythropoietin (rhEpo) producing clones were generated. The clone with highest productivity, RS-1C9 was further characterized and showed stable productivity. Biological activity was observed in in vitro assays and 28% of rhEpo glyco-isoforms produced by RS-1C9 were in range and distribution of the biological reference standard (BRP) isoform, as compared to 11.5% of a CHO based rhEpo. Additionally, cellular α-2,6 sialylation, Galactose-alpha-1,3-galactose (alpha-Gal) and N-glycolylneuraminic acid (NeuGc) patterns compare favourably to CHO cells. While productivity of RS still needs optimization, its amenability to upscaling in bioreactors, its production of glyco-isoforms that will increase yields after down-stream processing of about 2.5 fold, presence of sialylation and lack of Neu5Gc recommend RS as alternative human host cell line for production of biopharmaceuticals. © 2014 Elsevier B.V.


PubMed | University of Natural Resources and Life Sciences, Vienna and ACIB
Type: | Journal: Journal of biotechnology | Year: 2014

Human host cell lines for the production of biopharmaceutical proteins are of interest due to differences in the glycosylation patterns of human and animal cell lines. Specifically, sialylation, which has a major impact on half-life and immunogenicity of recombinant biopharmaceuticals, differs markedly. Here, we established and characterized an immortalized well documented and serum-free host cell line, RS, from primary human renal proximal tubular epithelial cells (RPTEC). In order to test its capacity to produce complex glycosylated proteins, stable recombinant human erythropoietin (rhEpo) producing clones were generated. The clone with highest productivity, RS-1C9 was further characterized and showed stable productivity. Biological activity was observed in in vitro assays and 28% of rhEpo glyco-isoforms produced by RS-1C9 were in range and distribution of the biological reference standard (BRP) isoform, as compared to 11.5% of a CHO based rhEpo. Additionally, cellular -2,6 sialylation, Galactose-alpha-1,3-galactose (alpha-Gal) and N-glycolylneuraminic acid (NeuGc) patterns compare favourably to CHO cells. While productivity of RS still needs optimization, its amenability to upscaling in bioreactors, its production of glyco-isoforms that will increase yields after down-stream processing of about 2.5 fold, presence of sialylation and lack of Neu5Gc recommend RS as alternative human host cell line for production of biopharmaceuticals.


PubMed | University of Natural Resources and Life Sciences, Vienna and ACIB
Type: Journal Article | Journal: New biotechnology | Year: 2015

Transient gene expression (TGE) is an essential tool for the production of recombinant proteins, especially in early drug discovery and development phases of biopharmaceuticals. The need for fast production of sufficient recombinant protein for initial tests has dramatically increased with increase in the identification of potential novel pharmaceutical targets. One of the critical factors for transient transfection is plasmid copy number (PCN), for which we here provide an optimized qPCR based protocol. Thereby, we show the loss of PCN during a typical batch process of HEK293 cells after transfection from 606,000 to 4560 copies per cell within 5 days. Finally two novel human kidney cell lines, RS and RPTEC/TERT1 were compared to HEK293 and proved competitive in terms of PCN and specific productivity. In conclusion, since trafficking and degradation of plasmid DNA is not fully understood yet, improved methods for analysis of PCN may contribute to design specific and more stable plasmids for high yield transient gene expression systems.


Fliedl L.,ACIB | Wieser M.,ACIB | Manhart G.,ACIB | Gerstl M.P.,ACIB | And 3 more authors.
ALTEX | Year: 2014

Nephrotoxicity of chemotherapeutics is a major hindrance in the treatment of various tumors. Therefore, test systems that reflect mechanisms of human kidney toxicity are necessary, and to reduce animal testing cell culture based systems have to be developed. One cell type that is of specific interest in this regard are renal proximal tubular epithelial cells, as they reabsorb substances from human primary urine filtrates and thus are exposed to urinary excreted xenobiotics and are a major target of cisplatin toxicity. While animal studies using gamma glutamyl transferase (GGT) knock-out mice or GGT inhibitors show that GGT activity increases kidney toxicity of cisplatin, the use of various cell models gives contradictory results. We therefore used a cell panel of immortalized human renal proximal tubular epithelial (RPTECs) cell lines differing in GGT activity. Low GGT activity resulted in high cisplatin sensitivity, as observed in RPTEC-SV40 cells or after siRNA mediated knock-down of GGT in RPTEC/TERT1 cells that have high GGT activity. However, the addition of GGT did not rescue, but also increased cisplatin sensitivity and adding GGT inhibitor as well as substrate (glutathione) or product (cysteinyl-glycine) of GGT resulted in decreased sensitivity. While our data suggest that the use of cell panels are of value in toxicology and toxicogenomics, they also emphasize on the complex interplay of toxins with the intracellular and extracellular microenvironment. In addition, we hypothesize that especially epithelial barrier formation and polarity of RPTECs need to be considered in toxicity models to validly predict the in vivo situation.

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