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PDBsum entry 1uiw
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Oxygen storage/transport
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PDB id
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1uiw
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Contents |
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* Residue conservation analysis
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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 structures of unliganded and half-Liganded human hemoglobin derivatives cross-Linked between lys 82beta1 and lys 82beta2.
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Authors
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S.Y.Park,
N.Shibayama,
T.Hiraki,
J.R.Tame.
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Ref.
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Biochemistry, 2004,
43,
8711-8717.
[DOI no: ]
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PubMed id
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Abstract
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A number of ligand binding studies of human adult hemoglobin (HbA) cross-linked
between Lys 82beta(1) and Lys 82beta(2) with bis(3,5-dibromosalicyl)fumarate
have been reported. The oxygen binding properties of native HbA, including the
cooperativity and Bohr effect, are not substantially changed by the
modification, provided care is taken to remove electrophoretically silent
impurities arising from side reactions. We have refined the high-resolution
structure of this modified Hb and found it adopts the T state when crystallized
in the absence of heme ligands, contrary to a previously published structure.
These results suggest the slightly altered crystal form determined previously
may be due to unremoved side products of the cross-linking reaction with high
oxygen affinity. Two nickel-substituted Hbs cross-linked in the same way have
also been crystallized in the presence of carbon monoxide, which binds only to
the ferrous heme. In the case of the nickel-substituted alpha subunit, the
absence of a covalent link between the central metal of the heme and the
proximal histidine leads to a new conformation of the histidine stabilized by a
water molecule. This structure may mimic that of partially NO-liganded species
of HbA; however, overall, the changes are highly localized, and both doubly
ligated species are in the T conformation.
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