|
We report here the purification and characterization of a c-type cytochrome
present in the soluble fraction of the gram-positive, alkaliphilic, and highly
ureolytic soil bacterium Bacillus pasteurii. The cytochrome is acidic (pI =
3.3), has a molecular mass of 9.5 kDa, and appears to dimerize in 150 mM ionic
strength solution. The electronic spectrum is typical of a low-spin
hexa-coordinated heme iron. Crystals of the protein in the oxidized state were
grown by vapor diffusion at pH 5, by using 3.2 M ammonium sulfate as
precipitant. Diffraction data at ultrahigh resolution (0.97 A) and completeness
(99.9%) have been collected under cryogenic conditions, by using synchrotron
radiation. The crystals belong to the orthorhombic space group P2(1)2(1)2(1),
with cell constants a = 37.14, b = 39.42, c = 44.02 A, and one protein monomer
per asymmetric unit. Attempts to solve the crystal structure by ab initio
methods are in progress.
|
