Sy. Park et al., CRYSTALLIZATION, PRELIMINARY DIFFRACTION AND ELECTRON-PARAMAGNETIC-RESONANCE STUDIES OF A SINGLE-CRYSTAL OF CYTOCHROME P450NOR, FEBS letters, 412(2), 1997, pp. 346-350
Cytochrome P450nor (P450nor) is a heme-containing nitric oxide reducta
se from the denitrifying fungus, Fusarium oxysporum. This enzyme catal
yzes the reduction of NO to N2O, In the present study, we report resul
ts from preliminary crystallographic and electron paramagnetic resonan
ce (EPR) analysis of a single crystal of P450nor, The crystal was grow
n in 100 mM MES buffer at pH 5.6 using PEG 4000 as a precipitant, It b
elongs to the orthorhombic system with cell dimensions of a=54.99 Angs
trom, b=82.66 Angstrom, c=87.21 Angstrom, and the space group is P2(1)
2(1)2(1). The crystal diffracts synchrotron radiation at higher than 2
.0 Angstrom resolution, and therefore it is suitable for X-ray crystal
structure analysis at atomic resolution, Bijvoet and dispersive anoma
lous difference Patterson maps show a clear peak corresponding to the
heme iron, The structure solution is currently underway bg means of MI
R and MAD techniques, EPR analysis determined the orientation of the h
eme within the P450nor crystal. (C) 1997 Federation of European Bioche
mical Societies.