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PDBsum entry 1a0x
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Oxygen transport
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PDB id
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1a0x
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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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High-Resolution crystal structures of human hemoglobin with mutations at tryptophan 37beta: structural basis for a high-Affinity t-State,.
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Authors
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J.S.Kavanaugh,
J.A.Weydert,
P.H.Rogers,
A.Arnone.
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Ref.
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Biochemistry, 1998,
37,
4358-4373.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
88%.
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Abstract
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The high-resolution X-ray structures of the deoxy forms of four recombinant
hemoglobins in which Trp37(C3)beta is replaced with Tyr (betaW37Y), Ala
(betaW37A), Glu (betaW37E), or Gly (betaW37G) have been refined and analyzed
with superposition methods that partition mutation-induced perturbations into
quaternary structure changes and tertiary structure changes. In addition, a new
cross-validation statistic that is sensitive to local changes in structure (a
"local Rfree" parameter) was used as an objective measure of the significance of
the tertiary structure changes. No significant mutation-induced changes in
tertiary structure are detected at the mutation site itself for any of the four
mutants studied. Instead, disruption of the intersubunit contacts associated
with Trp37(C3)beta results in (1) a change in quaternary structure at the
alpha1beta2 interface, (2) alpha subunit tertiary structure changes that are
centered at Asp94(G1)alpha-Pro95(G2)alpha, (3) beta subunit tertiary structure
changes that are located between residues Asp99(G1)beta and Asn102(G4)beta, (4)
increased mobility of the alpha subunit COOH-terminal dipeptide, and (5)
shortening of the Fe-Nepsilon2His(F8) bond in the alpha and beta subunits of the
betaW37G and betaW37E mutants. In each case, the magnitude of the change in a
particular structural parameter increases in the order betaW37Y < betaW37A
< betaW37E approximately betaW37G, which corresponds closely to the degree of
functional disruption documented in the preceding papers.
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