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  • 1
    Electronic Resource
    Electronic Resource
    Crystallization of the oxygen-evolving reaction centre of photosystem II in nine different detergent mixtures (1999)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 891-894 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Oxygen-evolving photosystem II reaction centres (RCII) isolated from both spinach and pea have been crystallized. A single crystal form grew from RCII monomers in the presence of nine different three-component mixtures of non-ionic detergents and heptane-1,2,3-triol. The crystals grew as hexagonal rods with dimensions of up to 1 × 0.3 × 0.3 mm. The crystals diffracted to a maximum resolution of 6.5 Å and belong to a hexagonal space group with unit-cell parameters a = 495, b = 495, c = 115 Å, α = β = 90, γ = 120°. The growth of a single crystal form in the presence of such a large variety of detergents suggests a very limited range of crystal lattice formation sites in the RCII complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444998016497
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  • 2
    Electronic Resource
    Electronic Resource
    Crystallization of dimers of the manganese-stabilizing protein of Photosystem II (2000)
    Springer
    Photosynthesis research 64 (2000), S. 167-177 
    Details
    ISSN: 1573-5079
    Keywords: dynamic light scattering ; mass spectrometry ; oxygen evolution ; photosynthesis ; protein crystallization ; protein structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The manganese-stabilizing protein (MSP) of Photosystem II was purified from spinach photosynthetic membranes. The MSP was crystallized in the presence of calcium. Despite the apparent purity of the isolated protein, the crystals grew to only about 0.05 mm in their largest dimension. The MSP was analyzed to identify possible sources of protein heterogeneity that could hinder crystal growth. Tandem reverse-phase HPLC/ electronspray ionization mass spectrometry analysis of the MSP showed a major peak and four smaller peaks. All five peaks had molecular masses of 26 535, as expected for mature MSP, indicating the absence of heterogeneities due to covalent modifications. MALDI mass spectroscopy was utilized to identify heterogeneities in the MSP oligomeric state. These measurements showed that purified MSP in solution is a mixture of monomers and dimers, while solubilized MSP crystals contained only dimers. Size-exclusion chromatography and dynamic light scattering were used to probe the effect of the crystallization conditions on the MSP. Size-exclusion chromatography of concentrated MSP showed the presence of aggregates and monomers, while dilute MSP contained monomers. Dynamic light scattering experiments in the absence, or in the presence of 10–50 mM or 100 mM calcium, yielded calculated molecular mass values of 34 kDa, 48 kDa and 68 kDa, respectively. These changes in the observed molecular mass of the MSP could have been caused by the formation of dimers and higher oligomers and/or significant conformational changes. Based on the results reported in this study, a model is presented which details the effect of oligomeric heterogeneity on the inhibition of MSP crystal growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006453718502
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  • 3
    Electronic Resource
    Electronic Resource
    Analysis of the role of detergent mixtures on the crystallization of the reaction center of Photosystem II (2000)
    Springer
    Photosynthesis research 65 (2000), S. 249-259 
    Details
    ISSN: 1573-5079
    Keywords: dynamic light scattering ; membrane protein crystallization ; photosynthesis ; thermoluminescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have recently reported the crystallization of the reaction center of Photosystem II in the presence of detergent mixtures [Adir N (1999) Acta Crystallogr D Biol Crystallogr D55: 891–894]. We have used high performance liquid chromatography, dynamic light scattering, native gel electrophoresis and thermoluminescence measurements to characterize the interaction between these detergent mixtures and RC II, to try and understand their role in the crystallization process. Size exclusion HPLC and dynamic light scattering confirmed that the isolated RC II used for crystallization was exclusively monomeric. Dynamic light scattering measurements show that the detergent mixtures formed single micelles within a limited range of hydrodynamic radii. Both size exclusion HPLC and dynamic light scattering were used to follow the interaction between the detergent mixtures and monomeric RC II. These techniques revealed a decrease in the detergent mixture treated RC II particle size (with respect with the untreated RC II), and that RC II from solubilized crystals contained particles of the same size. Native gel electrophoresis showed that this change in apparent size is not due to the disintegration of the internal structure of the RC II complex. Thermoluminescence measurements of solubilized RC II crystals showed charge recombination from the S2,3QA − state, indicating that RC II remains functionally viable following detergent mixture treatment and crystallization. The role of the detergent mixtures in the crystallization of RC II is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010618527974
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    EPR and ENDOR studies of the water oxidizing complex of Photosystem II (1996)
    Springer
    Photosynthesis research 48 (1996), S. 227-237 
    Details
    ISSN: 1573-5079
    Keywords: manganese cluster ; multiline signal ; oxygen evolution ; S-states ; water ligation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A comparative study of X-band EPR and ENDOR of the S2 state of photosystem II membrane fragments and core complexes in the frozen state is presented. The S2 state was generated either by continuous illumination at T=200 K or by a single turn-over light flash at T=273 K yielding entirely the same S2 state EPR signals at 10 K. In membrane fragments and core complex preparations both the multiline and the g=4.1 signals were detected with comparable relative intensity. The absence of the 17 and 23 kDa proteins in the core complex preparation has no effect on the appearance of the EPR signals. 1H-ENDOR experiments performed at two different field positions of the S2 state multiline signal of core complexes permitted the resolution of four hyperfine (hf) splittings. The hf coupling constants obtained are 4.0, 2.3, 1.1 and 0.6 MHz, in good agreement with results that were previously reported (Tang et al. (1993) J Am Chem Soc 115: 2382–2389). The intensities of all four line pairs belonging to these hf couplings are diminished in D2O. A novel model is presented and on the basis of the two largest hfc's distances between the manganese ions and the exchangeable protons are deduced. The interpretation of the ENDOR data indicates that these hf couplings might arise from water which is directly ligated to the manganese of the water oxidizing complex in redox state S2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00041013
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    Paper (German National Licenses)
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