Wolfgang Lubitz

Max Planck Institute for Chemical Energy Conversion, Mülheim-on-Ruhr, North Rhine-Westphalia, Germany

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Publications (381)1398.71 Total impact

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    ABSTRACT: Please find the abstract attached as a separate word file "abstract".
    Journal of the American Chemical Society 07/2014; · 10.68 Impact Factor
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    ABSTRACT: A series of four [S2Ni(μ-S)2FeCp*Cl] compounds with different tetradentate thiolate/thioether ligands bound to the Ni(II) ion is reported (Cp* = C5Me5). The {S2Ni(μ-S)2Fe} core of these compounds resembles structural features of the active site of [NiFe] hydrogenases. Detailed analyses of the electronic structures of these compounds by Mössbauer and electron paramagnetic resonance spectroscopy, magnetic measurements, and density functional theory calculations reveal the oxidation states Ni(II) low spin and Fe(II) high spin for the metal ions. The same electronic configurations have been suggested for the Cred1 state of the C-cluster [NiFeu] subsite in carbon monoxide dehydrogenases (CODH). The Ni-Fe distance of ∼3 Å excludes a metal-metal bond between nickel and iron, which is in agreement with the computational results. Electrochemical experiments show that iron is the redox active site in these complexes, performing a reversible one-electron oxidation. The four complexes are discussed with regard to their similarities and differences both to the [NiFe] hydrogenases and the C-cluster of Ni-containing CODH.
    Inorganic chemistry. 06/2014;
  • Johannes Messinger, Wolfgang Lubitz, Jian-Ren Shen
    Physical chemistry chemical physics : PCCP. 05/2014;
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    ABSTRACT: The EPR "split signals" represent key intermediates of the S-state cycle where the redox active D1-Tyr161 (YZ) has been oxidized by the reaction center of the photosystem II enzyme to its tyrosyl radical form, but the successive oxidation of the Mn4CaO5 cluster has not yet occurred (SiYZ˙). Here we focus on the S2YZ˙ state, which is formed en route to the final metastable state of the catalyst, the S3 state, the state which immediately precedes O-O bond formation. Quantum chemical calculations demonstrate that both isomeric forms of the S2 state, the open and closed cubane isomers, can form states with an oxidized YZ˙ residue without prior deprotonation of the Mn4CaO5 cluster. The two forms are expected to lie close in energy and retain the electronic structure and magnetic topology of the corresponding S2 state of the inorganic core. As expected, tyrosine oxidation results in a proton shift towards His190. Analysis of the electronic rearrangements that occur upon formation of the tyrosyl radical suggests that a likely next step in the catalytic cycle is the deprotonation of a terminal water ligand (W1) of the Mn4CaO5 cluster. Diamagnetic metal ion substitution is used in our calculations to obtain the molecular g-tensor of YZ˙. It is known that the gx value is a sensitive probe not only of the extent of the proton shift between the tyrosine-histidine pair, but also of the polarization environment of the tyrosine, especially about the phenolic oxygen. It is shown for PSII that this environment is determined by the Ca(2+) ion, which locates two water molecules about the phenoxyl oxygen, indirectly modulating the oxidation potential of YZ.
    Physical Chemistry Chemical Physics 04/2014; · 3.83 Impact Factor
  • Chemical Reviews 03/2014; · 41.30 Impact Factor
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    ABSTRACT: The combination of high-field EPR with site-directed spin-labeling (SDSL) techniques employing nitroxide radicals has turned out to be particularly powerful in probing the polarity and proticity characteristics of protein/matrix systems. This information is concluded from the principal components of the nitroxide Zeeman (g), nitrogen hyperfine (A) and quadrupole (P) tensors of the spin labels attached to specific sites. Recent multi-frequency high-field EPR studies underlined the complexity of the problem to treat the nitroxide microenvironment in proteins adequately due to inherent heterogeneities which result in several principal x-components of the nitroxide g-tensor. Concomitant, but distinctly different nitrogen hyperfine components could, however, not be determined from high-field cw EPR experiments owing to the large intrinsic EPR linewidth in fully protonated guest/host systems. It is shown in this work that, using the W-band (95GHz) ELDOR- (electron-electron double resonance) detected NMR (EDNMR) method, different principal nitrogen hyperfine, Azz, and quadrupole, Pzz, tensor values of a nitroxide radical in glassy 2-propanol matrix can be measured with high accuracy. They belong to nitroxides with different hydrogen-bond situations. The satisfactory resolution and superior sensitivity of EDNMR as compared to the standard ENDOR (electron-nuclear double resonance) method are demonstrated.
    Journal of Magnetic Resonance 03/2014; 242C:203-213. · 2.30 Impact Factor
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    ABSTRACT: The S2 state of the oxygen-evolving complex of photosystem II, which consists of a Mn4O5Ca cofactor, is EPR-active, typically displaying a multiline signal, which arises from a ground spin state of total spin ST = 1/2. The precise appearance of the signal varies amongst different photosynthetic species, preparation and solvent conditions/compositions. Over the past five years, using the model species Thermosynechococcus elongatus, we have examined modifications that induce changes in the multiline signal, i.e. Ca(2+)/Sr(2+)-substitution and the binding of ammonia, to ascertain how structural perturbations of the cluster are reflected in its magnetic/electronic properties. This refined analysis, which now includes high-field (W-band) data, demonstrates that the electronic structure of the S2 state is essentially invariant to these modifications. This assessment is based on spectroscopies that examine the metal centres themselves (EPR, (55)Mn-ENDOR) and their first coordination sphere ligands ((14)N/(15)N- and (17)O-ESEEM, -HYSCORE and -EDNMR). In addition, extended quantum mechanical models from broken-symmetry DFT now reproduce all EPR, (55)Mn and (14)N experimental magnetic observables, with the inclusion of second coordination sphere ligands being crucial for accurately describing the interaction of NH3 with the Mn tetramer. These results support a mechanism of multiline heterogeneity reported for species differences and the effect of methanol [Biochim. Biophys. Acta, Bioenerg., 2011, 1807, 829], involving small changes in the magnetic connectivity of the solvent accessible outer MnA4 to the cuboidal unit Mn3O3Ca, resulting in predictable changes of the measured effective (55)Mn hyperfine tensors. Sr(2+) and NH3 replacement both affect the observed (17)O-EDNMR signal envelope supporting the assignment of O5 as the exchangeable μ-oxo bridge and it acting as the first site of substrate inclusion.
    Physical Chemistry Chemical Physics 02/2014; · 3.83 Impact Factor
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    ABSTRACT: Membrane type 1 matrix metalloproteinase (MT1-MMP) belongs to the large family of zinc-dependent endopeptidases termed MMPs that are located in the extracellular matrix. MT1-MMP was crystallized at 277 K using the vapour-diffusion method with PEG as a precipitating agent. Data sets for MT1-MMP were collected to 2.24 Å resolution at 100 K. The crystals belonged to space group P43212, with unit-cell parameters a = 62.99, c = 122.60 Å. The crystal contained one molecule per asymmetric unit, with a Matthews coefficient (VM) of 2.90 Å(3) Da(-1); the solvent content is estimated to be 57.6%.
    Acta crystallographica. Section F, Structural biology communications. 02/2014; 70(Pt 2):232-5.
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    ABSTRACT: Synthesis and X-ray structural analyses of three NiS4 compounds with aliphatic tetradentate thiolato/thioether ligands―[Ni(xch)], [Ni(pdtch)], and [Ni(pdtdm)], in which H2xch, H2pdtch, and H2pdtdm are α,α′-bis(trans-2-mercapto-1-thiacyclohexyl)-o-xylene, 1,3-bis(trans-2-mercapto-1-thiacyclohexyl)propane, and 1,9-dimercapto-3,7-dithia-2,2,8,8-tetramethylnonane―are reported and further investigated by NMR spectroscopy, electronic absorption spectroscopy, and cyclic voltammetry. The molecular and electronic structures of these nickel complexes are described. All complexes are square planar and show only a small tetrahedral distortion, consistent with a low-spin nickel(II) center (S = 0). Cyclic voltammetry data reveal that for all compounds both one-electron oxidation and reduction are irreversible, which is explained by means of DFT calculations. The presented complexes are discussed with regard to their suitability as precursors for dinuclear [NiFe]–hydrogenase model compounds.
    Berichte der deutschen chemischen Gesellschaft 01/2014; 2014(1). · 2.94 Impact Factor
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    ABSTRACT: Base metal, molecular catalysts for the fundamental process of conversion of protons and electrons to dihydrogen, remain a substantial synthetic goal related to a sustainable energy future. Here we report a diiron complex with bridging thiolates in the butterfly shape of the 2Fe2S core of the [FeFe]-hydrogenase active site but with nitrosyl rather than carbonyl or cyanide ligands. This binuclear [(NO)Fe(N2S2)Fe(NO)2](+) complex maintains structural integrity in two redox levels; it consists of a (N2S2)Fe(NO) complex (N2S2=N,N'-bis(2-mercaptoethyl)-1,4-diazacycloheptane) that serves as redox active metallodithiolato bidentate ligand to a redox active dinitrosyl iron unit, Fe(NO)2. Experimental and theoretical methods demonstrate the accommodation of redox levels in both components of the complex, each involving electronically versatile nitrosyl ligands. An interplay of orbital mixing between the Fe(NO) and Fe(NO)2 sites and within the iron nitrosyl bonds in each moiety is revealed, accounting for the interactions that facilitate electron uptake, storage and proton reduction.
    Nature Communications 01/2014; 5:3684. · 10.02 Impact Factor
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    ABSTRACT: Some organisms can survive complete dehydration and high temperatures by adopting an anhydrobiotic state in which the intracellular medium contains large amounts of disaccharides, particularly trehalose and sucrose. Trehalose is most effective also in protecting isolated in vitro biostructures. In an attempt to clarify the molecular mechanisms of disaccharide bioprotection, we compared the structure and dynamics of sucrose and trehalose matrices at different hydration levels by means of high-field W-band EPR and FTIR spectroscopy. The hydration state of the samples was characterized by FTIR spectroscopy and the structural organization was probed by EPR using a nitroxide radical dissolved in the respective matrices. Analysis of the EPR spectra showed that the structure and dynamics of the dehydrated matrices as well as their evolution upon re-hydration differ substantially between trehalose and sucrose. The dehydrated trehalose matrix is homogeneous in terms of distribution of the residual water and spin-probe molecules. In contrast, dehydrated sucrose forms a heterogeneous matrix. It is comprised of sucrose polycrystalline clusters and several bulk water domains. The amorphous form was found only in 30% (volume) of the sucrose matrix. Re-hydration leads to a structural homogenization of the sucrose matrix, whilst in the trehalose matrix several domains develop differing in the local water/radical content and radical mobility. The molecular model of the matrices provides an explanation for the different protein-matrix dynamical coupling observed in dried ternary sucrose and trehalose matrices, and accounts for the superior efficacy of trehalose as a bioprotectant. Furthermore, for bacterial photosynthetic reaction centers it is shown that at low water content the protein-matrix coupling is modulated by the sugar/protein molar ratio in sucrose matrices only. This effect is suggested to be related to the preference for sucrose, rather than trehalose, as a bioprotective disaccharide in some anhydrobiotic organisms.
    Physical Chemistry Chemical Physics 12/2013; · 3.83 Impact Factor
  • Klaus Möbius, Wolfgang Lubitz, Anton Savitsky
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    ABSTRACT: In this review on advanced EPR spectroscopy, which addresses both the EPR and NMR communities, considerable emphasis is put on delineating the complementarity of NMR and EPR concerning the measurement of molecular interactions in large biomolecules. From these interactions, detailed information can be revealed on structure and dynamics of macromolecules embedded in solution- or solid-state environments. New developments in pulsed microwave and sweepable cryomagnet technology as well as ultrafast electronics for signal data handling and processing have pushed to new horizons the limits of EPR spectroscopy and its multifrequency extensions concerning the sensitivity of detection, the selectivity with respect to interactions, and the resolution in frequency and time domains. One of the most important advances has been the extension of EPR to high magnetic fields and microwave frequencies, very much in analogy to what happens in NMR. This is exemplified by referring to ongoing efforts for signal enhancement in both NMR and EPR double-resonance techniques by exploiting dynamic nuclear or electron spin polarization via unpaired electron spins and their electron-nuclear or electron-electron interactions. Signal and resolution enhancements are particularly spectacular for double-resonance techniques such as ENDOR and PELDOR at high magnetic fields. They provide greatly improved orientational selection for disordered samples that approaches single-crystal resolution at canonical g-tensor orientations - even for molecules with small g-anisotropies. Exchange of experience between the EPR and NMR communities allows for handling polarization and resolution improvement strategies in an optimal manner. Consequently, a dramatic improvement of EPR detection sensitivity could be achieved, even for short-lived paramagnetic reaction intermediates. Unique structural and dynamic information is thus revealed that can hardly be obtained by any other analytical techniques. Micromolar quantities of sample molecules have become sufficient to characterize stable and transient reaction intermediates of complex molecular systems - offering highly interesting applications for chemists, biochemists and molecular biologists. In three case studies, representative examples of advanced EPR spectroscopy are reviewed: (I) High-field PELDOR and ENDOR structure determination of cation-anion radical pairs in reaction centers from photosynthetic purple bacteria and cyanobacteria (Photosystem I); (II) High-field ENDOR and ELDOR-detected NMR spectroscopy on the oxygen-evolving complex of Photosystem II; and (III) High-field electron dipolar spectroscopy on nitroxide spin-labelled bacteriorhodopsin for structure-function studies. An extended conclusion with an outlook to further developments and applications is also presented.
    Progress in Nuclear Magnetic Resonance Spectroscopy 11/2013; 75:1-49. · 6.02 Impact Factor
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    ABSTRACT: Although metallocofactors are ubiquitous in enzyme catalysis, how metal binding specificity arises remains poorly understood, especially in the case of metals with similar primary ligand preferences such as manganese and iron. The biochemical selection of manganese over iron presents a particularly intricate problem because manganese is generally present in cells at a lower concentration than iron, while also having a lower predicted complex stability according to the Irving-Williams series (Mn(II) < Fe(II) < Ni(II) < Co(II) < Cu(II) > Zn(II)). Here we show that a heterodinuclear Mn/Fe cofactor with the same primary protein ligands in both metal sites self-assembles from Mn(II) and Fe(II) in vitro, thus diverging from the Irving-Williams series without requiring auxiliary factors such as metallochaperones. Crystallographic, spectroscopic, and computational data demonstrate that one of the two metal sites preferentially binds Fe(II) over Mn(II) as expected, whereas the other site is nonspecific, binding equal amounts of both metals in the absence of oxygen. Oxygen exposure results in further accumulation of the Mn/Fe cofactor, indicating that cofactor assembly is at least a two-step process governed by both the intrinsic metal specificity of the protein scaffold and additional effects exerted during oxygen binding or activation. We further show that the mixed-metal cofactor catalyzes a two-electron oxidation of the protein scaffold, yielding a tyrosine-valine ether cross-link. Theoretical modeling of the reaction by density functional theory suggests a multistep mechanism including a valyl radical intermediate.
    Proceedings of the National Academy of Sciences 10/2013; · 9.74 Impact Factor
  • Nicholas Cox, Wolfgang Lubitz, Anton Savitsky
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    ABSTRACT: ELDOR-detected NMR (EDNMR) spectra for a series of hydrated transition metal complexes: MnII(H2O)6, CuII(H2O)6 and VIVO(H2O)5 are reported. All EDNMR experiments were performed at W-band (94 GHz) employing two independent microwave frequencies. A purpose-built broadband microwave resonator (spectral range 300 MHz) was used, sufficient to detect all single quantum nuclear transitions of the three model systems. The EDNMR spectral lineshape observed is essentially the same as in conventional ENDOR (Electron-Nuclear Double Resonance). EDNMR presents two technical advantages over ENDOR for transition metal complexes: (i) enhanced sensitivity, reducing acquisition times by at least one order of magnitude; and (ii) simultaneous detection of transitions from all magnetic nuclei. This includes ligand (1H, 2H, 17O) and metal centred hyperfine couplings. For the latter, both isotropic couplings in the case of the 55Mn complex and highly anisotropic couplings in the case of 51V and 63,65Cu complexes could be resolved. By monitoring the intensity of the EDNMR lines as function of the amplitude of the pumping microwave pulse, transitions from non-equivalent nuclei can be differentiated. Double quantum transitions are also readily identified. In case of the MnII(H217O)6 complex, spectral lines involving the simultaneous pumping of both the 55Mn and 17O nuclear transitions are observed.
    Molecular Physics 10/2013; 111(18-19):2788-2808. · 1.67 Impact Factor
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    ABSTRACT: A detailed characterization of a close synthetic model of the [2 Fe]H subcluster in the [FeFe] hydrogenase active site is presented. It contains the full primary coordination sphere of the CO-inhibited oxidized state of the enzyme including the CN(-) ligands and the azadithiolate (adt) bridge, [((μ-SCH2 )2 NR)Fe2 (CO)4 (CN)2 ](2-) , R=CH2 CH2 SCH3 . The electronic structure of the model complex in its Fe(I) Fe(II) state was investigated by means of density functional theory (DFT) calculations and Fourier transform infrared (FTIR) spectroscopy. By using a combination of continuous-wave (CW) electron paramagnetic resonance (EPR) and hyperfine sublevel correlation (HYSCORE) experiments as well as DFT calculations, it is shown that, for this complex, the spin density is delocalized over both iron atoms. Interestingly, we found that the nitrogen hyperfine coupling, which represents the interaction between the unpaired electron and the nitrogen at the dithiolate bridge, is slightly larger than that in the analogous complex in which the CN(-) ligands are replaced with PMe3 ligands. This reveals, first, that the CN(-) /PMe3 ligands coordinated to the iron core are electronically coupled to the amine in the adt bridge. Second, the CN(-) ligands in this complex are somewhat stronger σ-donor ligands than the PMe3 ligand, and thereby enable more spin density to be transferred from the Fe core to the adt unit, which might in turn affect the reactivity of the bridging amine.
    Chemistry 09/2013; · 5.93 Impact Factor
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    ABSTRACT: The assignment of the two substrate water sites of the tetra-manganese penta-oxygen calcium (Mn4O5Ca) cluster of photosystem II is essential for the elucidation of the mechanism of biological O-O bond formation and the subsequent design of bio-inspired water-splitting catalysts. We recently demonstrated using pulsed EPR spectroscopy that one of the five oxygen bridges (μ-oxo) exchanges unusually rapidly with bulk water and is thus a likely candidate for one of the substrates. Ammonia, a water analog, was previously shown to bind to the Mn4O5Ca cluster, potentially displacing a water/substrate ligand [Britt RD, et al. (1989) J Am Chem Soc 111(10):3522-3532]. Here we show by a combination of EPR and time-resolved membrane inlet mass spectrometry that the binding of ammonia perturbs the exchangeable μ-oxo bridge without drastically altering the binding/exchange kinetics of the two substrates. In combination with broken-symmetry density functional theory, our results show that (i) the exchangable μ-oxo bridge is O5 {using the labeling of the current crystal structure [Umena Y, et al. (2011) Nature 473(7345):55-60]}; (ii) ammonia displaces a water ligand to the outer manganese (MnA4-W1); and (iii) as W1 is trans to O5, ammonia binding elongates the MnA4-O5 bond, leading to the perturbation of the μ-oxo bridge resonance and to a small change in the water exchange rates. These experimental results support O-O bond formation between O5 and possibly an oxyl radical as proposed by Siegbahn and exclude W1 as the second substrate water.
    Proceedings of the National Academy of Sciences 09/2013; · 9.74 Impact Factor
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    ABSTRACT: Characterizing a new hydrogenase: The newly isolated [NiFeSe] hydrogenase from Desulfovibrio vulgaris Miyazaki F displays catalytic properties distinct from other hydrogenase proteins. Here we apply site-specific spectroscopic and electrochemical techniques to characterize these unique features at the molecular level.
    ChemBioChem 09/2013; · 3.74 Impact Factor
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    ABSTRACT: Hydrogenases catalyze the formation of hydrogen. The cofactor ('H-cluster') of [FeFe]-hydrogenases consists of a [4Fe-4S] cluster bridged to a unique [2Fe] subcluster whose biosynthesis in vivo requires hydrogenase-specific maturases. Here we show that a chemical mimic of the [2Fe] subcluster can reconstitute apo-hydrogenase to full activity, independent of helper proteins. The assembled H-cluster is virtually indistinguishable from the native cofactor. This procedure will be a powerful tool for developing new artificial H2-producing catalysts.
    Nature Chemical Biology 08/2013; · 12.95 Impact Factor
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    ABSTRACT: Electrochemical SEIRA is the method of choice for characterizing a lipid-bilayer-anchored, membrane-bound hydrogenase immobilized on a gold electrode. This setup allows the study of the enzyme under conditions mimicking its natural environment. A single experiment provides all of the crucial spectroscopic information relating to the protein orientation, active site of the protein, and the lipid bilayer and also direct electrochemical determination of the catalytic H2 oxidation by the enzyme.
    Journal of Physical Chemistry Letters 08/2013; 4(17):2794–2798. · 6.59 Impact Factor
  • Proceedings of the National Academy of Sciences 07/2013; 110(28):E2539. · 9.74 Impact Factor

Publication Stats

4k Citations
1,398.71 Total Impact Points


  • 2005–2014
    • Max Planck Institute for Chemical Energy Conversion
      Mülheim-on-Ruhr, North Rhine-Westphalia, Germany
  • 1975–2013
    • Freie Universität Berlin
      • • Department of Physics
      • • Institute of Experimental Physics
      • • Division of Organic Chemistry
      Berlín, Berlin, Germany
  • 2003–2012
    • Max Planck Institute for Chemistry
      Mayence, Rheinland-Pfalz, Germany
    • University of California, Davis
      Davis, California, United States
  • 2010–2011
    • Weizmann Institute of Science
      • Department of Plant Sciences
  • 1991–2010
    • Technische Universität Berlin
      • Department of Chemistry
      Berlin, Land Berlin, Germany
  • 2008–2009
    • Ruhr-Universität Bochum
      • Fachbereich Biochemie
      Bochum, North Rhine-Westphalia, Germany
    • University of Bonn
      • Institute of Physical and Theoretical Chemistry
      Bonn, North Rhine-Westphalia, Germany
  • 2005–2009
    • Max Planck Institute for Empirical Aesthetics
      Frankfurt, Hesse, Germany
  • 1996–2008
    • Arizona State University
      • • The Center for Bioenergy and Photosynthesis
      • • Department of Chemistry and Biochemistry
      Tempe, AZ, United States
  • 1984–2007
    • University of California, San Diego
      • Department of Physics
      San Diego, CA, United States
  • 2004
    • Università degli Studi di Siena
      • Department of Medicine, Surgery and Neuroscience
      Siena, Tuscany, Italy
  • 2000
    • University of Glasgow
      Glasgow, Scotland, United Kingdom
  • 1998
    • The University of Sheffield
      Sheffield, England, United Kingdom
    • Ludwig-Maximilian-University of Munich
      • Department of Internal Medicine I
      München, Bavaria, Germany
  • 1995
    • University of Wuerzburg
      • Julius-von-Sachs-Institut of Biosciences
      Würzburg, Bavaria, Germany