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  • 1
    Electronic Resource
    Electronic Resource
    Structure Solution of Azurin II from Alcaligenes xylosoxidans using the Laue Method: Possibility of Studying In Situ Redox Changes using X-rays (1996)
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 3 (1996), S. 14-19 
    Details
    ISSN: 1600-5775
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: We have recently demonstrated that X-rays can be used for changing the redox states of the metal centre in metalloproteins [Murphy et al. (1995). J. Synchrotron Rad. 2, 64–69]. The possibility of using the Laue method for studying the structural changes associated with such X-ray-induced reactions is explored by applying the method to the structure determination of a new azurin (hereafter referred to as azurin II) from the denitrifying bacterium Alcaligenes xylosoxidans. Laue X-ray diffraction data of azurin II were collected at station 9.7 of the SRS Daresbury. Three diffraction patterns were recorded on film packs at three different crystal orientations. The data were processed using the Daresbury Laue Software Suite to give 2224 independent single reflections (Rmerge = 0.136) in the wavelength range 0.36–1.40 Å. The data completeness was 44% at 2.55 Å resolution. Phase determination for the data was undertaken using the molecular-replacement method; the top peak was chosen in both the rotation function and the subsequent translation function. This solution agreed well with the molecular-replacement solution achieved independently using monochromatic data. The electron-density map showed reasonably good agreement with the model and the copper site was readily recognizable as it had the highest density. To see if the electron-density map could be improved, `the doublets in the diffraction data were then deconvoluted. This added 26% data in the region ∞-2dmin resulting in an improvement in the data completeness to 50% and thus in improved continuity of the electron-density map. The quality of these maps is discussed from the point of view of the suitability of this approach for studying redox-induced structural changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0909049595013240
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  • 2
    Electronic Resource
    Electronic Resource
    Structure of a new azurin from the denitrifying bacterium Alcaligenes xylosoxidans at high resolution (1995)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 51 (1995), S. 1052-1064 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: It has been reported previously that Alcaligenes xylosoxidans (NC1MB 11015) grown under denitrifying conditions produces two azurins instead of the single previously identified azurin [Dodd, Hasnain, Hunter, Abraham, Debenham, Kanzler, Eldridge, Eady, Ambler & Smith (1995). Biochemistry. In the press]. The new azurin, called azurin II, has been crystallized as blue elongated rectangular prisms with the tetragonal space group P4122 and unit-cell parameters a = b = 52.65, c = 100.63 Å. X-ray crystallographic data extending to 1.9 Å resolution were collected by the Weissenberg method using 200 × 400 mm image plates and synchrotron X-rays of wavelength 0.97 Å. The three-dimensional structure of azurin II has been solved by the molecular-replacement method using the structure of azurin from Alcaligenes denitrificans NCTC 8582 with which this new azurin shows a close homology. The quality of the initial map was sufficient to predict a number of sequence differences. The model is currently refined to an R-factor of 18.8% with X-ray data between 8.5 and 1.9 Å. The final model of 961 protein atoms, one Cu atom and 50 water molecules has r.m.s. deviations from ideality of 0.009 Å for bond lengths and 1.7° for bond angles. The overall structure is similar to that of the azurin from A. denitrificans NCTC 8582. It has a β-barrel structure with the Cu atom located near the top end of the molecule. The Cu atom is coordinated to Nδ of His46 and His117 at 2.02 Å and to Sγ of Cys112 at 2.12 Å, while the carbonyl O atom of Gly45 and Sδ atom of Met121 provide the additional interactions at 2.75 and 3.26 Å, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444995007554
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  • 3
    Electronic Resource
    Electronic Resource
    Structures of a Blue-Copper Nitrite Reductase and its Substrate-Bound Complex (1997)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 53 (1997), S. 406-418 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Copper-containing nitrite reductases (NiR's) have been conveniently subdivided into blue and green NiR's which are thought to be redox partners of azurins and pseudo-azurins, respectively. Crystal structures of two green NiR's have recently been determined. Alcaligenes xylosoxidans has been shown to have a blue-copper nitrite reductase (AxNiR) and two azurins with 67% homology both of which donate electrons to it effectively. The first crystal structure of a blue NiR (AxNiR) in its oxidized and nitrite-bound forms, with particular emphasis to the Cu sites, is presented. The Cu-Smet distance is the same as those in the green NiR's. Thus, the length of this interaction is unlikely to be responsible for differences in colour. Crystallographic data presented here taken together with structural data of other single Cu type-1 proteins and their mutants suggest that the displacement of Cu from the strong ligand plane is perhaps the cause for the differences in colour observed for otherwise `classical' blue Cu centre. Nitrite is observed binding to the catalytic Cu in a bidentate fashion displacing the water molecule, offering a neat rationalization for the XAFS observation that the type-2 Cu-ligand distances increase on nitrite binding as a result of increased coordination. These results are discussed in terms of enzyme mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444997002667
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  • 4
    Electronic Resource
    Electronic Resource
    Nucleic acid binding drugs. XVII. Structures of 4-substituted analogues of the antitumour drug amsacrine (1987)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 43 (1987), S. 1992-1995 
    Details
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108270187089327
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    Paper (German National Licenses)
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