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PDBsum entry 2d6c
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Oxygen storage/transport
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PDB id
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2d6c
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References listed in PDB file
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Key reference
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Title
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Crystal structure and peroxidase activity of myoglobin reconstituted with iron porphycene.
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Authors
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T.Hayashi,
D.Murata,
M.Makino,
H.Sugimoto,
T.Matsuo,
H.Sato,
Y.Shiro,
Y.Hisaeda.
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Ref.
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Inorg Chem, 2006,
45,
10530-10536.
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PubMed id
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Abstract
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The incorporation of an artificially created metal complex into an apomyoglobin
is one of the attractive methods in a series of hemoprotein modifications.
Single crystals of sperm whale myoglobin reconstituted with
13,16-dicarboxyethyl-2,7-diethyl-3,6,12,17-tetramethylporphycenatoiron(III) were
obtained in the imidazole buffer, and the 3D structure with a 2.25-A resolution
indicates that the iron porphycene, a structural isomer of hemin, is located in
the normal position of the heme pocket. Furthermore, it was found that the
reconstituted myoglobin catalyzed the H2O2-dependent oxidations of substrates
such as guaiacol, thioanisole, and styrene. At pH 7.0 and 20 degrees C, the
initial rate of the guaiacol oxidation is 11-fold faster than that observed for
the native myoglobin. Moreover, the stopped-flow analysis of the reaction of the
reconstituted protein with H2O2 suggested the formation of two reaction
intermediates, compounds II- and III-like species, in the absence of a
substrate. It is a rare example that compound III is formed via compound II in
myoglobin chemistry. The enhancement of the peroxidase activity and the
formation of the stable compound III in myoglobin with iron porphycene mainly
arise from the strong coordination of the Fe-His93 bond.
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