TY - JOUR A1 - Poyraz, Ö. A1 - Schmidt, H. A1 - Seidel, K. A1 - Delißen, Friedmar A1 - Ader, C. A1 - Tenenboim, H. A1 - Goosmann, C. A1 - Laube, B. A1 - Thünemann, Andreas A1 - Zychlinsky, A. A1 - Baldus, M. A1 - Lange, A. A1 - Griesinger, C. A1 - Kolbe, M. T1 - Protein refolding is required for assembly of the type three secretion needle N2 - Pathogenic Gram-negative bacteria use a type three secretion system (TTSS) to deliver virulence factors into host cells. Although the order in which proteins incorporate into the growing TTSS is well described, the underlying assembly mechanisms are still unclear. Here we show that the TTSS needle protomer refolds spontaneously to extend the needle from the distal end. We developed a functional mutant of the needle protomer from Shigella flexneri and Salmonella typhimurium to study its assembly in vitro. We show that the protomer partially refolds from α-helix into β-strand conformation to form the TTSS needle. Reconstitution experiments show that needle growth does not require ATP. Thus, like the structurally related flagellar systems, the needle elongates by subunit polymerization at the distal end but requires protomer refolding. Our studies provide a starting point to understand the molecular assembly mechanisms and the structure of the TTSS at atomic level. PY - 2010 DO - https://doi.org/10.1038/nsmb.1822 SN - 1545-9993 SN - 1545-9985 VL - 17 SP - 788 EP - 792 PB - Nature Publ. Comp. CY - New York, NY, USA AN - OPUS4-21726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Duan, X.R. A1 - Lange, H. A1 - Meyer-Plath, Asmus T1 - Absolute density distribution of H atoms in a large-scale microwave plasma reactor N2 - Absolute number densities and the spatial distribution of atomic hydrogen in a large-scale microwave plasma reactor were measured by means of two-photon absorption laser-induced fluorescence (LIF) with laser radiation at 205 nm. The microwave discharge was operated at 2.45 GHz with a maximum power of 2 kW. Absolute number densities were obtained by calibrating the LIF detection system via NO2 titration in a flow tube reactor and in the range from 0.5×1015 to 2.5×1015 cm-3. Compared to small-scale reactors with a volume-to-surface ratio less than 3 cm, this reactor has a relatively homogeneous spatial distribution of atomic hydrogen. The mole fraction of atomic hydrogen in hydrogen plasmas ranges from 10% to 20%. The gas temperature–volume effect plays an important role in the spatial distribution of atomic hydrogen in this reactor. PY - 2003 DO - https://doi.org/10.1088/0963-0252/12/4/307 SN - 0963-0252 SN - 1361-6595 VL - 12 SP - 554 EP - 560 PB - IOP Publ. CY - Bristol AN - OPUS4-2696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Juds, Carmen A1 - Schmidt, J. A1 - Weller, Michael G. A1 - Lange, Thorid A1 - Beck, Uwe A1 - Conrad, T. A1 - Boerner, H. G. T1 - Combining phage display and next-generation sequencing for materials sciences: A case study on probing polypropylene surfaces N2 - Phage display biopanning with Illumina next-generation sequencing (NGS) is applied to reveal insights into peptide-based adhesion domains for polypropylene (PP). One biopanning round followed by NGS selects robust PP-binding peptides that are not evident by Sanger sequencing. NGS provides a significant statistical base that enables motif analysis, statistics on positional residue depletion/enrichment, and data analysis to suppress false-positive sequences from amplification bias. The selected sequences are employed as water-based primers for PP-metal adhesion to condition PP surfaces and increase adhesive strength by 100% relative to nonprimed PP. KW - Polymers KW - Polypropylene KW - Glue KW - Plastics KW - Surface Activation KW - Primer KW - Peptide Library KW - Epoxy KW - Solid-binding Peptides KW - Functionalization KW - Polymer-binding Peptides KW - Adhesion KW - Material-binding Peptides KW - Adhesives PY - 2020 DO - https://doi.org/10.1021/jacs.0c03482 SN - 0002-7863 SN - 1520-5126 VL - 142 IS - 24 SP - 10624 EP - 10628 PB - ACS CY - Washington, DC, USA AN - OPUS4-51123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Janiak, Ch. A1 - Lange, K.C.H. A1 - Marquardt, P. A1 - Krüger, Ralph-Peter A1 - Hanselmann, R. T1 - Analyses of Propene and 1-Hexene Oligomers from Zirconocene/MAO Catalysts - Mechanistic Implications by NMR, SEC and MALDI-TOF MS N2 - A series of Cp(C5H5)ZrCl2 and Cp2ZrCl2 pre-catalysts (Cp = C5HMe4, C4Me4P, C5Me5, C5H4tBu, C5H3-1,3-tBu2, C5H2-1,2,4-tBu3) together with (C5H5)2ZrCl2 was used for the directed oligomerization of propene and 1-hexene in comparative experiments. Oligomer characterization was carried out by 1H NMR, SEC (GPC), MALDI-TOF MS, cryoscopy and Raman spectroscopy. From 1H NMR the nature and relative ratio of the double-bond end group is determined together with n if every oligomer molecule contains such a double-bond end group. Normally vinylidene double bonds (from -hydrogen elimination) are found. From 1H NMR and MALDI-TOF MS also vinyl end groups (from -methyl elimination) are observed in the case of oligopropenes with (C4Me4P)- (C5H5)ZrCl2 and with the symmetrical methyl containing Cp2ZrCl2 pre-catalysts. The vinylidene/vinyl ratio depends on the ligand and increases from C5HMe4 (65/35) over C4Me4P (61/39) to C5Me5 (9/91). A comparison of n from 1H NMR and SEC together with MALDI-TOF MS shows that the phospholyl-zirconocenes and (C5HMe4)2ZrCl2 also exhibit chain transfer to aluminium, thereby giving saturated oligomers. KW - Chain transfer KW - MALDI KW - Metallocene catalysts KW - Oligomers KW - Polyolefins PY - 2002 DO - https://doi.org/10.1002/1521-3935(20020101)203:1<129::AID-MACP129>3.0.CO;2-C SN - 1022-1352 SN - 1521-3935 VL - 203 IS - 1 SP - 129 EP - 138 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -