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PDBsum entry 2zpp
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References listed in PDB file
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Key reference
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Title
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An abnormal pk(a) value of internal histidine of the insulin molecule revealed by neutron crystallographic analysis.
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Authors
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T.Ishikawa,
T.Chatake,
Y.Morimoto,
M.Maeda,
K.Kurihara,
I.Tanaka,
N.Niimura.
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Ref.
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Biochem Biophys Res Commun, 2008,
376,
32-35.
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PubMed id
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Abstract
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Insulin is stored in pancreatic beta-cell as hexameric form with Zn2+ ions,
while the hormonally active form is monomer. The hexamer requires the
coordination of Zn2+ ions to the HisB10. In order to reveal the mechanism of the
hexamerization of insulin, we investigated the Zn2+ free insulin at pD6.6 and
pD9 by neutron crystallographic analyses. HisB10 is doubly protonated not only
at pD6.6 but also at pD9, indicating an abnormal pK(a) of this histidine. It is
suggested that HisB10 acts on a strong cation capture and contributes to the
high stability of the hexameric form in pancreas.
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