1jgc
From Proteopedia
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The 2.6 A Structure Resolution of Rhodobacter capsulatus Bacterioferritin with Metal-free Dinuclear Site and Heme Iron in a Crystallographic Special Position
Overview
Bacterioferritin from Rhodobacter capsulatus was crystallized and its, structure was solved at 2.6 A resolution. This first structure of a, bacterioferritin from a photosynthetic organism is a spherical particle of, 24 subunits displaying 432 point-group symmetry like ferritin and, bacterioferritin from Escherichia coli. Crystallized in the I422 space, group, its structural analysis reveals for the first time the, non-symmetric heme molecule located on a twofold crystallographic symmetry, axis. Other hemes of the protomer are situated on twofold, noncrystallographic axes. Apparently, both types of sites bind heme in two, orientations, leading to an average structure consisting of a symmetric, 50:50 mixture, thus satisfying the crystallographic and, noncrystallographic symmetry of the crystal. Five water molecules are, situated close to the heme, which is bound in a hydrophobic pocket and, axially coordinated by two crystallographic or noncrystallographically, related methionine residues. Its ferroxidase center, in which Fe(II) is, oxidized to Fe(III), is empty or fractionally occupied by a metal ion. Two, positions are observed for the coordinating Glu18 side chain instead of, one in the E. coli enzyme in which the site is occupied. This result, suggests that the orientation of the Glu18 side chain could be constrained, by this interaction.
About this Structure
1JGC is a Single protein structure of sequence from Rhodobacter capsulatus with HEM as ligand. Full crystallographic information is available from OCA.
Reference
The 2.6 A resolution structure of Rhodobacter capsulatus bacterioferritin with metal-free dinuclear site and heme iron in a crystallographic 'special position'., Cobessi D, Huang LS, Ban M, Pon NG, Daldal F, Berry EA, Acta Crystallogr D Biol Crystallogr. 2002 Jan;58(Pt 1):29-38. Epub 2001, Dec 21. PMID:11752777
Page seeded by OCA on Tue Nov 20 18:13:24 2007
