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PDBsum entry 2qpp
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Oxidoreductase
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PDB id
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2qpp
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References listed in PDB file
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Key reference
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Title
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Comparison of apo- And heme-Bound crystal structures of a truncated human heme oxygenase-2.
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Authors
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C.M.Bianchetti,
L.Yi,
S.W.Ragsdale,
G.N.Phillips.
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Ref.
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J Biol Chem, 2007,
282,
37624-37631.
[DOI no: ]
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PubMed id
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Abstract
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Heme oxygenase (HO) catalyzes the first step in the heme degradation pathway.
The crystal structures of apo- and heme-bound truncated human HO-2 reveal a
primarily alpha-helical architecture similar to that of human HO-1 and other
known HOs. Proper orientation of heme in HO-2 is required for the regioselective
oxidation of the alpha-mesocarbon. This is accomplished by interactions within
the heme binding pocket, which is made up of two helices. The iron coordinating
residue, His(45), resides on the proximal helix. The distal helix contains
highly conserved glycine residues that allow the helix to flex and interact with
the bound heme. Tyr(154), Lys(199), and Arg(203) orient the heme through direct
interactions with the heme propionates. The rearrangements of side chains in
heme-bound HO-2 compared with apoHO-2 further elucidate HO-2 heme interactions.
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Figure 1.
FIGURE 1. Schematic of the overall reaction catalyzed by
heme oxygenase.
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Figure 5.
FIGURE 5. Electron density maps of apo- and heme-bound
HO-2. A, stereo view of the F[o] - F[c] map of the heme-bound
HO-2 heme pocket contoured at 3  . The heme group is
shown with carbon in gray, oxygen in red, and iron in orange.
The red spheres represent water molecules. B, stereo view of the
2 F[o] - F[c] of the hydrophobic region in the heme pocket of
apoHO-2 shown at 1 . The Triton X-100 is
shown with carbon in yellow and oxygen in red.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2007,
282,
37624-37631)
copyright 2007.
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