TY - JOUR A1 - Munter, L.M. A1 - Sieg, H. A1 - Bethge, T. A1 - Liebsch, F. A1 - Bierkandt, Frank A1 - Schleeger, M. A1 - Bittner, H.J. A1 - Heberle, J. A1 - Jakubowski, Norbert A1 - Hildebrand, P.W. A1 - Multhaup, G. T1 - Model peptides uncover the role of the beta-secretase transmembrane sequence in metal ion mediated oligomerization N2 - The β-secretase or β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is the enzyme responsible for the formation of amyloid-β peptides, which have a major role in Alzheimer pathogenesis. BACE1 has a transmembrane sequence (TMS), which makes it unique among related proteases. We noticed that the BACE1 TMS contains an uncommon sulfur-rich motif. The sequence MxxxCxxxMxxxCxMxC spans the entire TMS, resembles metal ion binding motifs, and is highly conserved among homologues. We used a synthetic 31-mer model peptide comprising the TMS to study metal ion binding and oligomerization. Applying diverse biochemical and biophysical techniques, we detected dimer and trimer formation of the TMS peptide with copper ions. Replacement of the central Cys466 by Ala essentially abolished these effects. We show that the peptide undergoes a redox reaction with copper ions resulting in a disulfide bridge involving Cys466. Further, we find peptide trimerization that depends on the presence of monovalent copper ions and the sulfhydryl group of Cys466. We identified Cys466 as a key residue for metal ion chelation and to be the core of an oligomerization motif of the BACE1-TMS peptide. Our results demonstrate a novel metal ion controlled oligomerization of the BACE1 TMS, which could have an enormous therapeutic importance against Alzheimer disease. KW - Enzymes KW - Amyloid formation KW - Alzheimer disease KW - Copper PY - 2013 DO - https://doi.org/10.1021/ja410812r SN - 0002-7863 SN - 1520-5126 VL - 135 IS - 51 SP - 19354 EP - 19361 PB - American Chemical Society CY - Washington, DC AN - OPUS4-30543 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert T1 - Development of ICP-MS based methods for label free detection of single cells T2 - European Winter Conference on Plasma Spectrochemistry CY - Kraków, Poland DA - 2013-02-09 PY - 2013 AN - OPUS4-27891 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, Janine A1 - Fettig, Ina A1 - Piechotta, Christian A1 - Philipp, Rosemarie A1 - Jakubowski, Norbert T1 - Tributylzinn in Gesamtwasserproben - Entwicklung eines Referenzverfahrens für die EU-Wasserrahmenrichtlinie PY - 2013 SN - 0016-3538 IS - 9 SP - 2 EP - 4 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-29040 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert T1 - Einführung in die anorganische Massenspektroskopie T2 - 46. Jahrestagung der Deutschen Gesellschaft für Massenspektrometrie CY - Berlin, Germany DA - 2013-03-10 PY - 2013 AN - OPUS4-28032 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Larissa A1 - Techritz, Sandra A1 - Jakubowski, Norbert A1 - Roos, P.H. T1 - A multi-parametric microarray for protein profiling: simultaneous analysis of 8 different cytochromes via differentially element tagged antibodies and laser ablation ICP-MS N2 - The paper presents a new multi-parametric protein microarray embracing the multi-analyte capabilities of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The combination of high throughput reverse phase protein microarrays with element tagged antibodies and LA-ICP-MS makes it possible to detect and quantify many proteins or biomarkers in multiple samples simultaneously. A proof of concept experiment is performed for the analysis of cytochromes particularly of cytochrome P450 enzymes, which play an important role in the metabolism of xenobiotics such as toxicants and drugs. With the aid of the LA-ICP-MS based multi-parametric reverse phase protein microarray it was possible to analyse 8 cytochromes in 14 different proteomes in one run. The methodology shows excellent detection limits in the lower amol range and a very good linearity of R² ≥ 0.9996 which is a prerequisite for the development of further quantification strategies. KW - Multi-parametric KW - Multiplexing KW - Microarray KW - Immunoassay KW - LA-ICP-MS KW - Cytochrome P450 PY - 2013 DO - https://doi.org/10.1039/c3an00468f SN - 0003-2654 SN - 1364-5528 VL - 138 IS - 21 SP - 6309 EP - 6315 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-29275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert T1 - LA-ICP-MS for the detection of (semi)metallo-proteins in biological samples after PAGE / 2-DE separations T2 - Vortrag bei Prof. Ogra, University of Pharmaceutical CY - Tokyo, Japan DA - 2013-10-01 PY - 2013 AN - OPUS4-29198 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert T1 - LA-ICP-MS for the detection of (semi)metallo-proteins in biological samples after PAGE / 2-DE separations T2 - Vortrag bei Prof. Zuruta, Chuo University CY - Tokyo, Japan DA - 2013-10-03 PY - 2013 AN - OPUS4-29201 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert T1 - Development of ICP-MS based methods for label free detection of (semi)metals T2 - Vortrag bei der Discussion Group Plasma Meeting im Institut of Technology CY - Tokyo, Japan DA - 2013-10-04 PY - 2013 AN - OPUS4-29204 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shigeta, K. A1 - Koellensperger, G. A1 - Rampler, E. A1 - Traub, Heike A1 - Rottmann, L. A1 - Panne, Ulrich A1 - Okino, A. A1 - Jakubowski, Norbert T1 - Sample introduction of single selenized yeast cells (Saccharomyces cerevisiae) by micro droplet generation into an ICP-sector field mass spectrometer for label-free detection of trace elements N2 - We have applied a micro droplet generator (µDG) for sample introduction of single selenized yeast cells into a sector field ICP-MS, which was operated in a fast scanning mode with sampling rates of up to 10 kHz, to measure single cells time resolved with 100 µs integration time. Selenized yeast cells have been used as a model system for preliminary investigation. The single cells to be measured have been embedded into droplets and it will be shown that the time duration of a single cell event always is about 400 to 500 µs, and thus comparable to the time duration of a droplet without a cell. A fixed droplet generation rate of 50 Hz produced equidistant signals in time of each droplet event and was advantageous to separate contribution from background and blank from the analytical signal. Open vessel digestion and a multielement analysis were performed with washed yeast cells and absolute amounts per single cell were determined for Na (0.91 fg), Mg (9.4 fg), Fe (5.9 fg), Cu (0.54 fg), Zn (1.2 fg) and Se (72 fg). Signal intensities from single cells have been measured for the elements Cu, Zn and Se, and histograms were calculated for about 1000 cell events. The mean elemental sensitivities measured here range from 0.7 counts per ag (Se) to 10 counts per ag (Zn) with RSD's from 49% (Zn) to 69% (Se) for about 1000 cell events. PY - 2013 DO - https://doi.org/10.1039/c3ja30370e SN - 0267-9477 SN - 1364-5544 VL - 28 IS - 5 SP - 637 EP - 645 PB - Royal Society of Chemistry CY - London AN - OPUS4-29448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert T1 - Development of ICP-MS based methods to study the uptake of nanoparticles by single cells T2 - 2nd QNano Integrating Conference CY - Prague, Czech Republic DA - 2013-02-27 PY - 2013 AN - OPUS4-27862 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -