TY - JOUR A1 - Albrecht, Tanja A1 - Haebel, Sophie A1 - Koch, Anke A1 - Krause, Ulrike A1 - Eckermann, Nora A1 - Steup, Martin T1 - Yeast glycogenin (Glg2p) produced in Escherichia coli is simultaneously glucosylated at two vicinal tyrosin residues but results in a reduced bacterial glycogen accumulation N2 - Saccharomyces cerevisiae possesses two glycogenin isoforms (designated as Glg1p and Glg2p) that both contain a conserved tyrosine residue, Tyr232. However, Glg2p possesses an additional tyrosine residue, Tyr230 and therefore two potential autoglucosylation sites. Glucosylation of Glg2p was studied using both matrix-assisted laser desorption ionization and electrospray quadrupole time of flight mass spectrometry. Glg2p, carrying a C-terminal (His(6)) tag, was produced in Escherichia coli and purified. By tryptic digestion and reversed phase chromatography a peptide (residues 219-246 of the complete Glg2p sequence) was isolated that contained 4-25 glucosyl residues. Following incubation of Glg2p with UDPglucose, more than 36 glucosyl residues were covalently bound to this peptide. Using a combination of cyanogen bromide cleavage of the protein backbone, enzymatic hydrolysis of glycosidic bonds and reversed phase chromatography, mono- and diglucosylated peptides having the sequence PNYGYQSSPAM were generated. MS/MS spectra revealed that glucosyl residues were attached to both Tyr232 and Tyr230 within the same peptide. The formation of the highly glucosylated eukaryotic Glg2p did not favour the bacterial glycogen accumulation. Under various experimental conditions Glg2p-producing cells accumulated approximately 30% less glycogen than a control transformed with a Glg2p lacking plasmid. The size distribution of the glycogen and extractable activities of several glycogen-related enzymes were essentially unchanged. As revealed by high performance anion exchange chromatography, the intracellular maltooligosaccharide pattern of the bacterial cells expressing the functional eukaryotic transgene was significantly altered. Thus, the eukaryotic glycogenin appears to be incompatible with the bacterial initiation of glycogen biosynthesis Y1 - 2004 ER - TY - THES A1 - Albrecht, Tanja T1 - Quartärstruktur, Funktion und Lokation der Pho 1-Phosphorylasen aus Solanum tuberosum L. Y1 - 1998 CY - Potsdam ER - TY - JOUR A1 - Albrecht, Tanja A1 - Koch, Anke A1 - Lode, Anja A1 - Greve, Burkhard A1 - Schneider-Mergener, Jens A1 - Steup, Martin T1 - Plastidic (Pho1-type) phosphorylase isoforms in potato (Solanum tuberosum L.) plants : expression analysis and immunochemical characterization Y1 - 2001 ER - TY - JOUR A1 - Albrecht, Tanja A1 - Greve, Burkhard A1 - Pusch, Kerstin A1 - Koßmann, Jens A1 - Buchner, Peter A1 - Wobus, Ulrich A1 - Steup, Martin T1 - Homo- and Heterodimers of Pho1-Type Phosphorylase Isoforms in Solanum tuberosum L. as Revealed by Sequence- Specific Antibodies Y1 - 1998 ER - TY - JOUR A1 - Fettke, Jörg A1 - Malinova, Irina A1 - Albrecht, Tanja A1 - Hejazi, Mahdi A1 - Steup, Martin T1 - Glucose-1-Phosphate transport into protoplasts and chloroplasts from leaves of arabidopsis JF - Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants N2 - Almost all glucosyl transfer reactions rely on glucose-1-phosphate (Glc-1-P) that either immediately acts as glucosyl donor or as substrate for the synthesis of the more widely used Glc dinucleotides, ADPglucose or UDPglucose. In this communication, we have analyzed two Glc-1-P-related processes: the carbon flux from externally supplied Glc-1-P to starch by either mesophyll protoplasts or intact chloroplasts from Arabidopsis (Arabidopsis thaliana). When intact protoplasts or chloroplasts are incubated with [U-C-14]Glc-1-P, starch is rapidly labeled. Incorporation into starch is unaffected by the addition of unlabeled Glc-6-P or Glc, indicating a selective flux from Glc-1-P to starch. However, illuminated protoplasts incorporate less C-14 into starch when unlabeled bicarbonate is supplied in addition to the C-14-labeled Glc-1-P. Mesophyll protoplasts incubated with [U-C-14] Glc-1-P incorporate C-14 into the plastidial pool of adenosine diphosphoglucose. Protoplasts prepared from leaves of mutants of Arabidopsis that lack either the plastidial phosphorylase or the phosphoglucomutase isozyme incorporate C-14 derived from external Glc-1-P into starch, but incorporation into starch is insignificant when protoplasts from a mutant possessing a highly reduced ADPglucose pyrophosphorylase activity are studied. Thus, the path of assimilatory starch biosynthesis initiated by extraplastidial Glc-1-P leads to the plastidial pool of adenosine diphosphoglucose, and at this intermediate it is fused with the Calvin cycle-driven route. Mutants lacking the plastidial phosphoglucomutase contain a small yet significant amount of transitory starch. Y1 - 2011 U6 - https://doi.org/10.1104/pp.110.168716 SN - 0032-0889 VL - 155 IS - 4 SP - 1723 EP - 1734 PB - American Society of Plant Physiologists CY - Rockville ER - TY - JOUR A1 - Fettke, Jörg A1 - Albrecht, Tanja A1 - Hejazi, Mahdi A1 - Mahlow, Sebastian A1 - Nakamura, Yasunori A1 - Steup, Martin T1 - Glucose 1-phosphate is efficiently taken up by potato (Solanum tuberosum) tuber parenchyma cells and converted to reserve starch granules N2 - Reserve starch is an important plant product but the actual biosynthetic process is not yet fully understood. Potato (Solanum tuberosum) tuber discs from various transgenic plants were used to analyse the conversion of external sugars or sugar derivatives to starch. By using in vitro assays, a direct glucosyl transfer from glucose 1-phosphate to native starch granules as mediated by recombinant plastidial phosphorylase was analysed. Compared with labelled glucose, glucose 6-phosphate or sucrose, tuber discs converted externally supplied [C-14] glucose 1-phosphate into starch at a much higher rate. Likewise, tuber discs from transgenic lines with a strongly reduced expression of cytosolic phosphoglucomutase, phosphorylase or transglucosidase converted glucose 1-phosphate to starch with the same or even an increased rate compared with the wild-type. Similar results were obtained with transgenic potato lines possessing a strongly reduced activity of both the cytosolic and the plastidial phosphoglucomutase. Starch labelling was, however, significantly diminished in transgenic lines, with a reduced concentration of the plastidial phosphorylase isozymes. Two distinct paths of reserve starch biosynthesis are proposed that explain, at a biochemical level, the phenotype of several transgenic plant lines. Y1 - 2010 UR - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0028-646X U6 - https://doi.org/10.1111/j.1469-8137.2009.03126.x SN - 0028-646X ER - TY - JOUR A1 - Gruden, Kristina A1 - Hren, Matjaz A1 - Herman, Ana A1 - Blejec, Andrej A1 - Albrecht, Tanja A1 - Selbig, Joachim A1 - Bauer, Christian G. A1 - Schuchardt, Johannes A1 - Or-Guil, Michal A1 - Zupancic, Klemen A1 - Svajger, Urban A1 - Stabuc, Borut A1 - Ihan, Alojz A1 - Kopitar, Andreja Natasa A1 - Ravnikar, Maja A1 - Knezevic, Miomir A1 - Rozman, Primoz A1 - Jeras, Matjaz T1 - A "Crossomics" study analysing variability of different components in peripheral blood of healthy caucasoid individuals JF - PLoS one N2 - Background: Different immunotherapy approaches for the treatment of cancer and autoimmune diseases are being developed and tested in clinical studies worldwide. Their resulting complex experimental data should be properly evaluated, therefore reliable normal healthy control baseline values are indispensable. Methodology/Principal Findings: To assess intra- and inter-individual variability of various biomarkers, peripheral blood of 16 age and gender equilibrated healthy volunteers was sampled on 3 different days within a period of one month. Complex "crossomics'' analyses of plasma metabolite profiles, antibody concentrations and lymphocyte subset counts as well as whole genome expression profiling in CD4(+)T and NK cells were performed. Some of the observed age, gender and BMI dependences are in agreement with the existing knowledge, like negative correlation between sex hormone levels and age or BMI related increase in lipids and soluble sugars. Thus we can assume that the distribution of all 39.743 analysed markers is well representing the normal Caucasoid population. All lymphocyte subsets, 20% of metabolites and less than 10% of genes, were identified as highly variable in our dataset. Conclusions/Significance: Our study shows that the intra- individual variability was at least two-fold lower compared to the inter-individual one at all investigated levels, showing the importance of personalised medicine approach from yet another perspective. Y1 - 2012 U6 - https://doi.org/10.1371/journal.pone.0028761 SN - 1932-6203 VL - 7 IS - 1 PB - PLoS CY - San Fransisco ER -