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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