Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Language
Year
  • 1
    Language: English
    In: Science (New York, N.Y.), 19 December 2014, Vol.346(6216), pp.1456-7
    Description: How do electric fields affect enzymatic processes? Binding and crystallographic studies have shown that electrostatic interactions are important in the substrate-binding step that initiates enzyme catalysis. However, for the subsequent steps, experimental data have been limited....
    Keywords: Static Electricity ; Ketosteroids -- Metabolism ; Steroid Isomerases -- Chemistry
    ISSN: 00368075
    E-ISSN: 1095-9203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: FEBS Letters, 15 December 2011, Vol.585(24), pp.3998-4001
    Description: ► The chromophore in the long-lived intermediate of ChR2-C128T is a free retinal. ► It differs from the reduced-retro form of bacteriorhodopsin despite similar UV spectra. ► The photocycle of ChR2-C128T involves a transient cleavage of the retinal–protein linkage. The photocycle of the light-activated channel, channelrhodopsin-2 C128T, has been studied by resonance Raman (RR) spectroscopy focussing on the intermediates P380 and P353 that constitute a side pathway in the recovery of the parent state. The P353 species displays a UV–vis absorption spectrum with a fine-structure reminiscent of the reduced-retro form of bacteriorhodopsin, whereas the respective RR spectra differ substantially. Instead, the RR spectra of the P380/P353 intermediate couple are closely related to that of a free retinal in the configuration. These findings imply that the parent state recovery via P380/P353 involves the transient hydrolysis and re-formation of the retinal–protein linkage.
    Keywords: Channelrhodopsin ; Photocycle ; Retinal ; Retroretinal ; Resonance Raman ; Bacteriorhodopsin ; Biology ; Chemistry ; Anatomy & Physiology
    ISSN: 0014-5793
    E-ISSN: 1873-3468
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Journal of the American Chemical Society, 12 September 2012, Vol.134(36), pp.14710-3
    Description: High-valent copper-nitrene intermediates have long been proposed to play a role in copper-catalyzed aziridination and amination reactions. However, such intermediates have eluded detection for decades, preventing the unambiguous assignments of mechanisms. Moreover, the electronic structure of the proposed copper-nitrene intermediates has also been controversially discussed in the literature. These mechanistic questions and controversy have provided tremendous motivation to probe the accessibility and reactivity of Cu(III)-NR/Cu(II)N(•)R species. In this paper, we report a breakthrough in this field that was achieved by trapping a transient copper-tosylnitrene species, 3-Sc, in the presence of scandium triflate. The sufficient stability of 3-Sc at -90 °C enabled its characterization with optical, resonance Raman, NMR, and X-ray absorption near-edge spectroscopies, which helped to establish its electronic structure as Cu(II)N(•)Ts (Ts = tosyl group) and not Cu(III)NTs. 3-Sc can initiate tosylamination of cyclohexane, thereby suggesting Cu(II)N(•)Ts cores as viable reactants in oxidation catalysis.
    Keywords: Copper -- Chemistry ; Imines -- Chemistry ; Lewis Acids -- Chemistry ; Mesylates -- Chemistry ; Organometallic Compounds -- Chemistry ; Scandium -- Chemistry ; Tosyl Compounds -- Chemistry
    ISSN: 00027863
    E-ISSN: 1520-5126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Article
    Article
    Language: English
    In: Angewandte Chemie International Edition, 21 June 2010, Vol.49(27), pp.4540-4541
    Description: : A novel application of Raman microscopy takes advantage of a spectral window to map the uptake and distribution of metal‐carbonyl‐based drugs in single cells. The approach provides information on cell structure and molecular structure simultaneously and may have significant impact on drug screening and on the analysis of cellular processes in general.
    Keywords: Antitumor Agents ; Carbonyl Ligands ; Cells ; Molecular Imaging ; Raman Microscopy
    ISSN: 1433-7851
    E-ISSN: 1521-3773
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Journal of the American Chemical Society, 16 July 2014, Vol.136(28), pp.9870-3
    Description: [NiFe] hydrogenases catalyze the reversible cleavage of hydrogen and, thus, represent model systems for the investigation and exploitation of emission-free energy conversion processes. Valuable information on the underlying molecular mechanisms can be obtained by spectroscopic techniques that monitor individual catalytic intermediates. Here, we employed resonance Raman spectroscopy and extended it to the entire binuclear active site of an oxygen-tolerant [NiFe] hydrogenase by probing the metal-ligand modes of both the Fe and, for the first time, the Ni ion. Supported by theoretical methods, this approach allowed for monitoring H-transfer from the active site and revealed novel insights into the so far unknown structure and electronic configuration of the hydrogen-binding intermediate of the catalytic cycle, thereby providing key information about catalytic intermediates and reactions of biological hydrogen activation.
    Keywords: Hydrogenase -- Chemistry
    ISSN: 00027863
    E-ISSN: 1520-5126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Journal of the American Chemical Society, 25 February 2015, Vol.137(7), pp.2555-64
    Description: Oxygen-tolerant [NiFe] hydrogenases are metalloenzymes that represent valuable model systems for sustainable H2 oxidation and production. The soluble NAD(+)-reducing [NiFe] hydrogenase (SH) from Ralstonia eutropha couples the reversible cleavage of H2 with the reduction of NAD(+) and displays a unique O2 tolerance. Here we performed IR spectroscopic investigations on purified SH in various redox states in combination with density functional theory to provide structural insights into the catalytic [NiFe] center. These studies revealed a standard-like coordination of the active site with diatomic CO and cyanide ligands. The long-lasting discrepancy between spectroscopic data obtained in vitro and in vivo could be solved on the basis of reversible cysteine oxygenation in the fully oxidized state of the [NiFe] site. The data are consistent with a model in which the SH detoxifies O2 catalytically by means of an NADH-dependent (per)oxidase reaction involving the intermediary formation of stable cysteine sulfenates. The occurrence of two catalytic activities, hydrogen conversion and oxygen reduction, at the same cofactor may inspire the design of novel biomimetic catalysts performing H2-conversion even in the presence of O2.
    Keywords: Catalytic Domain ; Hydrogenase -- Chemistry ; Nad -- Metabolism ; Oxygen -- Metabolism
    ISSN: 00027863
    E-ISSN: 1520-5126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: European Management Journal, June 2018, Vol.36(3), pp.381-391
    Description: This explorative empirical study investigates which sets of portfolio restructuring design characteristics, contingent on individual firm and industry characteristics, lead to successful business portfolio transformations. We draw on insights from the strategic change, strategic fit, and organizational turnaround literature and develop a contingency model for transformation success. To allow for complex configurations, we employ a set-theoretic approach based on fuzzy set qualitative comparative analysis (fsQCA). Our findings suggest that there is no single best strategy for restructuring a portfolio. Rather, there are multiple pathways to success in portfolio transformation, depending on a firm's competitive posture and industry environment. In particular, our results highlight the pivotal influence of prior firm performance and environmental jolts on the design of successful business portfolio restructuring (BPR) strategies.
    Keywords: Corporate Restructuring ; Business Portfolio Transformation ; Strategic Change ; Contingency Model ; Set-Theoretic Methods ; Fuzzy Set Qualitative Comparative Analysis (Fsqca) ; Business
    ISSN: 0263-2373
    E-ISSN: 1873-5681
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Biochemistry, 11 September 2012, Vol.51(36), pp.7040-2
    Description: Activation of the corrinoid [Fe-S] protein (CoFeSP), involved in reductive CO(2) conversion, requires the reduction of the Co(II) center by the [Fe-S] protein RACo, which according to the reduction potentials of the two proteins would correspond to an uphill electron transfer. In our resonance Raman spectroscopic work, we demonstrate that, as a conformational gate for the corrinoid reduction, complex formation of Co(II)FeSP and RACo specifically alters the structure of the corrinoid cofactor by modifying the interactions of the Co(II) center with the axial ligand. On the basis of various deletion mutants, the potential interaction domains on the partner proteins can be predicted.
    Keywords: Corrinoids -- Chemistry ; Iron-Sulfur Proteins -- Chemistry
    ISSN: 00062960
    E-ISSN: 1520-4995
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    In: Physical Chemistry Chemical Physics, 2011, Vol.13(36), pp.16146-16149
    Description: Structural models for the Ni-B state of the wild-type and C81S protein variant of the membrane-bound [NiFe] hydrogenase from Ralstonia eutropha H16 were derived by applying the homology model technique combined with molecular simulations and a hybrid quantum mechanical/molecular mechanical approach. The active site structure was assessed by comparing calculated and experimental IR spectra, confirming the view that the active site structure is very similar to those of anaerobic standard hydrogenases. In addition, the data suggest the presence of a water molecule in the second coordination sphere of the active centre.
    Keywords: Chemistry;
    ISSN: 1463-9076
    E-ISSN: 1463-9084
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: PLoS ONE, 01 January 2015, Vol.10(6), p.e0129940
    Description: Cytochrome cd1 nitrite reductases (cd1NiRs) catalyze the one-electron reduction of nitrite to nitric oxide. Due to their catalytic reaction, cd1NiRs are regarded as promising components for biosensing, bioremediation and biotechnological applications. Motivated by earlier findings that catalytic...
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages