2ZPP image
Entry Detail
PDB ID:
2ZPP
Keywords:
HORMONE
Title:
Neutron crystal structure of cubic insulin at pD9
Biological Source:
Source Organism:
Sus scrofa
PDB Version:
Deposition Date:
2008-07-26
Release Date:
2008-10-28
Method Details:
Experimental Method:
NEUTRON DIFFRACTION
Resolution:
2.50 Å
R-Value Free:
0.26
R-Value Work:
0.22
R-Value Observed:
0.22
Space Group:
I 21 3
2ZPP validation report
Macromolecular Entities
Protein Blast
Polymer Type:polypeptide(L)
Description:Insulin A chain
Chain IDs:A
Chain Length:21
Number of Molecules:1
Biological Source:Sus scrofa
UniProt ID:P01315 Pfam ID:PF00049
Protein Blast
Polymer Type:polypeptide(L)
Description:Insulin B chain
Chain IDs:B
Chain Length:30
Number of Molecules:1
Biological Source:Sus scrofa
UniProt ID:P01315 Pfam ID:PF00049
Ligand Molecules
DOD
Primary Citation
An abnormal pK(a) value of internal histidine of the insulin molecule revealed by neutron crystallographic analysis
Biochem.Biophys.Res.Commun. 376 32 35 (2008)
PMID: 18725203 DOI: 10.1016/j.bbrc.2008.08.071

Abstact

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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Primary Citation of related structures
2EFA