@article{DoscheLoehmannsroebenBieseretal.2002, author = {Dosche, Carsten and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Bieser, A. and Dosa, P. I. and Han, S. and Iwamoto, M. and Schleifenbaum, A. and Vollhardt, K. Peter C.}, title = {Photophysical properties of [N]phenylenes}, year = {2002}, language = {en} } @article{KoetseLaschewskyJonasetal.2002, author = {Koetse, Marc M. and Laschewsky, Andr{\´e} and Jonas, Alain M. and Verbiest, T.}, title = {Orientation of functional groups in polyelectrolyte multilayers studied by second-harmonic generation (SHG)}, issn = {0927-7757}, year = {2002}, language = {en} } @book{OPUS4-17551, title = {PSE, S{\"a}uren, Salze, Elekrolyse : von "Ein Sack voll Ionen" bis zu "So kann man Schienen schweißen" ; Klassen 7 bis 10}, series = {Z.E.U.S.-Materialien : Chemie}, volume = {2}, journal = {Z.E.U.S.-Materialien : Chemie}, editor = {Duvinage, Brigitte}, publisher = {Aulis Verl. Deubner}, address = {K{\"o}ln}, isbn = {3-7614-2355-1}, pages = {272 S.}, year = {2002}, language = {de} } @article{vanAaltenKomanderSynstadetal.2002, author = {van Aalten, Daan M. F. and Komander, David and Synstad, Bjoenar and Gaseidnes, Sigrid and Peter, Martin G. and Eijsink, Vincent G. H.}, title = {Structural Insights into the catalytic mechanism of a family 18 exochitinase}, year = {2002}, abstract = {Chitinase B (ChiB) from Serratia marcescens is a family 18 exochitinase whose catalytic domain has a TIM-barrel fold with a tunnel-shaped active site. We have solved structures of three ChiB complexes that reveal details of substrate binding, substrateassisted catalysis, and product displacement. The structure of an inactive ChiB mutant (E144Q) complexed with a pentameric substrate (binding in subsites 22 to 13) shows closure of the ''roof'' of the active site tunnel. It also shows that the sugar in the 21 position is distorted to a boat conformation, thus providing structural evidence in support of a previously proposed catalytic mechanism. The structures of the active enzyme complexed to Allosamidin (an analogue of a proposed reaction intermediate) and of the active enzyme soaked with pentameric substrate show events after cleavage of the glycosidic bond. The latter structure shows reopening of the roof of the active site tunnel and enzyme-assisted product displacement in the 11 and 12 sites, allowing a water molecule to approach the reaction center. Catalysis is accompanied by correlated structural changes in the core of the TIM barrel that involve conserved polar residues whose functions were hitherto unknown. These changes simultaneously contribute to stabilization of the reaction intermediate and alternation of the pKa of the catalytic acid during the catalytic cycle.}, language = {en} } @article{Linker2002, author = {Linker, Torsten}, title = {Selective reactions of transition-metal-generated radicals}, year = {2002}, language = {en} } @phdthesis{Janietz2002, author = {Janietz, Silvia}, title = {Zusammnenh{\"a}nge zwischen Struktur, elektrochemischem Redoxverhalten und dem Einsatz von organischen Halbleitern in der Elektronik}, pages = {78 S., Anh.}, year = {2002}, language = {de} } @article{HoustonShiomiAraietal.2002, author = {Houston, Douglas R. and Shiomi, Kazuro and Arai, Noriko and Omura, Satoshi and Peter, Martin G. and Turberg, Andreas and Synstad, Bjoenar and Eijsink, Vincent G. H. and Van Aalten, Daan M. F.}, title = {High-resolution structures of a chitinase complexed with natural product cyclopentapeptide inhibitors : mimicry of carbohydrate substrate}, year = {2002}, abstract = {Over the past years, family 18 chitinases have been validated as potential targets for the design of drugs against human pathogens that contain or interact with chitin during their normal life cycles. Thus far, only one potent chitinase inhibitor has been described in detail, the pseudotrisaccharide allosamidin. Recently, however, two potent natural-product cyclopentapeptide chitinase inhibitors, argifin and argadin, were reported. Here, we describe high- resoln. crystal structures that reveal the details of the interactions of these cyclopeptides with a family 18 chitinase. The structures are examples of complexes of a carbohydrate-processing enzyme with high-affinity peptide-based inhibitors and show in detail how the peptide backbone and side chains mimic the interactions of the enzyme with chitooligosaccharides. Together with enzymol. characterization, the structures explain why argadin shows an order of magnitude stronger inhibition than allosamidin, whereas argifin shows weaker inhibition. The peptides bind to the chitinase in remarkably different ways, which may explain the differences in inhibition consts. The two complexes provide a basis for structure-based design of potent chitinase inhibitors, accessible by std. peptide chem.}, language = {en} } @article{MangeneyFerrageJullienetal.2002, author = {Mangeney, Claire and Ferrage, Fabien and Jullien, Ludovic and Ouari, Olivier and R{\´e}ka{\"i}, El-Djouhar and Laschewsky, Andr{\´e} and Vikholm, Inger and Sadowski, Janusz W.}, title = {Synthesis and properties of water-soluble gold colloids covalently derivatized with neutral polymer monolayers}, year = {2002}, abstract = {Citrate-capped gold nanoparticles as well as planar gold surfaces can be efficiently grafted with a covalently attached polymer monolayer a few nanometers thick, by simple contact of the metal surface with dilute aqueous solutions of hydrophilic polymers that are end-capped with disulfide moieties, as shown by UV/vis absorption, dynamic light scattering, and surface plasmon resonance studies. The hydrophilic polymer-coated gold colloids can be freeze-dried and stored as powders that can be subsequently dissolved to yield stable aqueous dispersions, even at very large concentrations. They allow for applying filtrations, gel permeation chromatography, or centrifugation. They do not suffer from undesirable nonspecific adsorption of proteins while allowing the diffusion of small species within the hydrogel surface coating. In addition, specific properties of the original hydrophilic polymers are retained such as a lower critical solution temperature. The latter feature could be useful to enhance optical responses of functionalized gold surfaces toward interaction with various substrates.}, language = {en} } @article{GlinelMoussaJonasetal.2002, author = {Glinel, Karine and Moussa, Alain and Jonas, Alain M. and Laschewsky, Andr{\´e}}, title = {The influence of polyelectrolyte charge density on the formation of multilayers of strong polyelectrolytes at low ionic strength}, year = {2002}, abstract = {The influence of the charge density of polyelectrolytes on the growth of polyelectrolyte multilayers via layer- by-layer self-assembly from pure aqueous solutions was studied. Multilayers were built from strong polyanions, namely poly(styrenesulfonate) and an exfoliated synthetic hectorite, and cationic copolymers of diallyldimethylammonium chloride (DADMAC) with N-methyl-N-vinylformamide (NMVF) for which the composition and thus the charge density was varied systematically. The analysis of the system {cationic copolymer/poly(styrenesulfonate)} reveals that a critical linear charge density {\"I}c of 0.036 elementary charge/{\AA} of contour length is necessary to obtain stable multilayer growth in pure water. Above {\"I}c, the increment of thickness/deposition cycle varies with the linear charge density of the cationic copolymers, in good agreement with current theories of polyelectrolyte solutions. As linear charge density increases, the system passes successively through a charge-dependent ?Debye-Hu ckel? regime and then through a chargeindependent ?strong-screening? regime where counterion condensation dominates the behavior. Analogous results were obtained for the variation of the basal spacing of internally structured hybrid multilayers {cationic copolymer/hectorite}. However, by contrast with the first system, no critical linear charge density was found for the hybrid system. This is explained by additional, nonelectrostatic interactions between the clay platelets and the formamide fragment.}, language = {en} } @article{GermerKlodPeteretal.2002, author = {Germer, Antje and Klod, Sabrina and Peter, Martin G. and Kleinpeter, Erich}, title = {NMR spectroscopic and theoretical study of the complexation of the inhibitor allosamidin in the binding pocket of the plant chitinase hevamine}, year = {2002}, abstract = {Based on NMR spectroscopic information about the allosamidin-hevamine complex, ab initio MO calcns. of the ring current effect of the arom. moieties of Trp255, Tyr183 and Tyr6 of hevamine were carried out to investigate the role of these amino acid residues in binding interactions with allosamidin in soln. In addn., the intermol. steric compression effect on the 13C chem. shifts of the allosamizoline carbon atoms and the hydrogen bonding to Glu127 was identified. It can be inferred that the binding forces are strongest in the allosamizoline moiety of allosamidin.}, language = {en} }