Structure of a monoclinic crystal from of cyctochrome b1 (Bacterioferritin) from E. coli.
Crystals of E. coli cytochrome b1, alias bacterioferritin, were grown fr om a low ionic strength solution. The resulting monoclniic P21 structure was solved by molecular replacement and refined using noncrystallographi c symmetries applied to the fundamental unit, consisting of two protein subunits and a single haem. From the Patterson self-rotation results it was shown that the asymmetric unit of the monoclinic crystal consists of 12 such dimers and corresponds to a complete, nearly spherical, molecule of bacterioferritin (M4 = 450 kDa) of 432 point-group symmetry. It is thus the most symmetrical cytochrome. As previously determined for the tetragonal form, the haem is located in a special position on a local twofold axis of the dimer. A bimetal centre is also observed within the four-helix bundle of each monomer; a metal-binding site is located on the fourfold axis.
Dautant
A
A
Unité Biophysique Structurale, ERS133 CNRS, Université de Bordeaux 1, France.
Meyer
J B
JB
Yariv
J
J
Précigoux
G
G
Sweet
R M
RM
Kalb
A J
AJ
Frolow
F
F
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D003573:Cytochrome b Group / Q000737:chemistry*; D003625:Data Collection; D004926:Escherichia coli / Q000201:enzymology*; D005293:Ferritins / Q000737:chemistry*; D006418:Heme / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D003573:Cytochrome b Group; D006418:Heme; D005293:Ferritins; C018032:bacterioferritin