1izb
From Proteopedia
(New page: 200px<br /><applet load="1izb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1izb, resolution 2.0Å" /> '''ROLE OF B13 GLU IN IN...) |
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| - | [[Image:1izb.jpg|left|200px]]<br /><applet load="1izb" size=" | + | [[Image:1izb.jpg|left|200px]]<br /><applet load="1izb" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1izb, resolution 2.0Å" /> | caption="1izb, resolution 2.0Å" /> | ||
'''ROLE OF B13 GLU IN INSULIN ASSEMBLY: THE HEXAMER STRUCTURE OF RECOMBINANT MUTANT (B13 GLU-> GLN) INSULIN'''<br /> | '''ROLE OF B13 GLU IN INSULIN ASSEMBLY: THE HEXAMER STRUCTURE OF RECOMBINANT MUTANT (B13 GLU-> GLN) INSULIN'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The assembly of the insulin hexamer brings the six B13 glutamate | + | The assembly of the insulin hexamer brings the six B13 glutamate side-chains at the centre into close proximity. Their mutual repulsion is unfavourable and zinc co-ordination to B10 histidine is necessary to stabilize the well known zinc-containing hexamers. Since B13 is always a carboxylic acid in all known sequences of hexamer forming insulins, it is likely to be important in the hormone's biology. The mutation of B13 Glu-->Gln leads to a stable zinc-free hexamer with somewhat reduced potency. The structures of the zinc-free B13 Gln hexamer and the 2Zn B13 insulin hexamer have been determined by X-ray analysis and refined with 2.5 A and 2.0 A diffraction data, respectively. Comparisons show that in 2Zn B13 Gln insulin, the hexamer structure (T6) is very like that of the native hormone. On the other hand, the zinc-free hexamer assumes a quaternary structure (T3/R3) seen in the native 4Zn insulin hexamer, and normally associated only with high chloride ion concentrations in the medium. The crystal structures show the B13 Gln side-chains only contact water in contrast to the B13 glutamate in 2Zn insulin. The solvation of the B13 Gln may be associated with this residue favouring helix at B1 to B8. The low potency of the B13 Gln insulin also suggests the residue influences the hormone's conformation. |
==About this Structure== | ==About this Structure== | ||
| - | 1IZB is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with ZN as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1IZB is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with <scene name='pdbligand=ZN:'>ZN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IZB OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Sus scrofa]] | [[Category: Sus scrofa]] | ||
| - | [[Category: Dodson, G | + | [[Category: Dodson, G G.]] |
[[Category: Xiao, B.]] | [[Category: Xiao, B.]] | ||
[[Category: ZN]] | [[Category: ZN]] | ||
[[Category: hormone]] | [[Category: hormone]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:17:18 2008'' |
Revision as of 11:17, 21 February 2008
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ROLE OF B13 GLU IN INSULIN ASSEMBLY: THE HEXAMER STRUCTURE OF RECOMBINANT MUTANT (B13 GLU-> GLN) INSULIN
Overview
The assembly of the insulin hexamer brings the six B13 glutamate side-chains at the centre into close proximity. Their mutual repulsion is unfavourable and zinc co-ordination to B10 histidine is necessary to stabilize the well known zinc-containing hexamers. Since B13 is always a carboxylic acid in all known sequences of hexamer forming insulins, it is likely to be important in the hormone's biology. The mutation of B13 Glu-->Gln leads to a stable zinc-free hexamer with somewhat reduced potency. The structures of the zinc-free B13 Gln hexamer and the 2Zn B13 insulin hexamer have been determined by X-ray analysis and refined with 2.5 A and 2.0 A diffraction data, respectively. Comparisons show that in 2Zn B13 Gln insulin, the hexamer structure (T6) is very like that of the native hormone. On the other hand, the zinc-free hexamer assumes a quaternary structure (T3/R3) seen in the native 4Zn insulin hexamer, and normally associated only with high chloride ion concentrations in the medium. The crystal structures show the B13 Gln side-chains only contact water in contrast to the B13 glutamate in 2Zn insulin. The solvation of the B13 Gln may be associated with this residue favouring helix at B1 to B8. The low potency of the B13 Gln insulin also suggests the residue influences the hormone's conformation.
About this Structure
1IZB is a Protein complex structure of sequences from Sus scrofa with as ligand. Full crystallographic information is available from OCA.
Reference
Role of B13 Glu in insulin assembly. The hexamer structure of recombinant mutant (B13 Glu-->Gln) insulin., Bentley GA, Brange J, Derewenda Z, Dodson EJ, Dodson GG, Markussen J, Wilkinson AJ, Wollmer A, Xiao B, J Mol Biol. 1992 Dec 20;228(4):1163-76. PMID:1361949
Page seeded by OCA on Thu Feb 21 13:17:18 2008
Categories: Protein complex | Sus scrofa | Dodson, G G. | Xiao, B. | ZN | Hormone
