1bcf
From Proteopedia
THE STRUCTURE OF A UNIQUE, TWO-FOLD SYMMETRIC, HAEM-BINDING SITE
Structural highlights
Function[BFR_ECOLI] Iron-storage protein, whose ferroxidase center binds Fe(2+) ions, oxidizes them by dioxygen to Fe(3+), and participates in the subsequent Fe(3+) oxide mineral core formation within the central cavity of the protein complex. The mineralized iron core can contain as many as 2700 iron atoms/24-meric molecule.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBacterioferritin of Escherichia coli, also known as cytochrome b1, is a hollow, nearly spherical shell made up of 24 identical protein subunits and 12 haems. We have solved this structure in a tetragonal crystal form at 2.9 A resolution. We find that each haem is bound in a pocket formed by the interface between a pair of symmetry-related subunits. The quasi-twofold axis of the haem is closely aligned with the local twofold axis relating these subunits. The axial ligands of the haem are sulphurs of two equivalent methionyl residues (Met 52) from the symmetry-related subunits. A cluster of four water molecules is trapped in the gap between the upper edge of the haem and two extended protein loops which close off the haem from the outer aqueous environment. This is the first structure of a bis-methionine ligated haem-binding site and the first case of a twofold symmetric haem-binding site. Structure of a unique twofold symmetric haem-binding site.,Frolow F, Kalb AJ, Yariv J Nat Struct Biol. 1994 Jul;1(7):453-60. PMID:7664064[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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