1rcg
From Proteopedia
(New page: 200px<br /><applet load="1rcg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1rcg, resolution 2.2Å" /> '''BULLFROG RED CELL L F...) |
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| - | [[Image:1rcg.gif|left|200px]]<br /><applet load="1rcg" size=" | + | [[Image:1rcg.gif|left|200px]]<br /><applet load="1rcg" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1rcg, resolution 2.2Å" /> | caption="1rcg, resolution 2.2Å" /> | ||
'''BULLFROG RED CELL L FERRITIN SULFATE/MN/PH 6.3'''<br /> | '''BULLFROG RED CELL L FERRITIN SULFATE/MN/PH 6.3'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Ferritin is a highly conserved multisubunit protein in animals, plants and | + | Ferritin is a highly conserved multisubunit protein in animals, plants and microbes which assembles with cubic symmetry and transports hydrated iron ions and protons to and from a mineralized core in the protein interior. We report here the high resolution structures of recombinant amphibian red-cell L ferritin and two mutants solved under two sets of conditions. In one mutant, Glu56, 57, 58 and 60 were replaced with Ala, producing a lag phase in the kinetics of iron uptake. In the second mutant, His25 was replaced with Tyr with, at most, subtle effects on function. A molecule of betaine, used in the purification, is bound in all structures at the 2-fold axis near the recently identified heme binding site of bacterioferritin and horse spleen L ferritin. Comparisons of the five amphibian structures identify two regions of the molecule in which conformational flexibility may be related to function. The positions and interactions of a set of 10 to 18 side-chains, most of which are on the inner surface of the protein, are sensitive both to solution conditions and to the Glu-->Ala mutation. A subset of these side-chains and a chain of ordered solvent molecules extends from the vicinity of Glu56 to 58 and Glu60 to the 3-fold channel in the wild type protein and may be involved in the transport of either iron or protons. The "spine of hydration" is disrupted in the Glu-->Ala mutant. In contrast, H25Y mutation shifts the positions of backbone atoms between the site of the mutation and the 4-fold axis and side-chain positions throughout the structure; the largest changes in the position of backbone atoms are in the DE loop and E helix, approximately 10 A from the mutation site. In combination, these results indicate that solvation, structural plasticity and cooperative structural changes may play a role in ferritin function. Analogies with the structure and function of ion channel proteins such as annexins are noted. |
==About this Structure== | ==About this Structure== | ||
| - | 1RCG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rana_catesbeiana Rana catesbeiana] with BET as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1RCG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rana_catesbeiana Rana catesbeiana] with <scene name='pdbligand=BET:'>BET</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RCG OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Rana catesbeiana]] | [[Category: Rana catesbeiana]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Allewell, N | + | [[Category: Allewell, N M.]] |
| - | [[Category: Theil, E | + | [[Category: Theil, E C.]] |
[[Category: Trikha, J.]] | [[Category: Trikha, J.]] | ||
[[Category: BET]] | [[Category: BET]] | ||
[[Category: iron storage]] | [[Category: iron storage]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:49:25 2008'' |
Revision as of 12:49, 21 February 2008
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BULLFROG RED CELL L FERRITIN SULFATE/MN/PH 6.3
Overview
Ferritin is a highly conserved multisubunit protein in animals, plants and microbes which assembles with cubic symmetry and transports hydrated iron ions and protons to and from a mineralized core in the protein interior. We report here the high resolution structures of recombinant amphibian red-cell L ferritin and two mutants solved under two sets of conditions. In one mutant, Glu56, 57, 58 and 60 were replaced with Ala, producing a lag phase in the kinetics of iron uptake. In the second mutant, His25 was replaced with Tyr with, at most, subtle effects on function. A molecule of betaine, used in the purification, is bound in all structures at the 2-fold axis near the recently identified heme binding site of bacterioferritin and horse spleen L ferritin. Comparisons of the five amphibian structures identify two regions of the molecule in which conformational flexibility may be related to function. The positions and interactions of a set of 10 to 18 side-chains, most of which are on the inner surface of the protein, are sensitive both to solution conditions and to the Glu-->Ala mutation. A subset of these side-chains and a chain of ordered solvent molecules extends from the vicinity of Glu56 to 58 and Glu60 to the 3-fold channel in the wild type protein and may be involved in the transport of either iron or protons. The "spine of hydration" is disrupted in the Glu-->Ala mutant. In contrast, H25Y mutation shifts the positions of backbone atoms between the site of the mutation and the 4-fold axis and side-chain positions throughout the structure; the largest changes in the position of backbone atoms are in the DE loop and E helix, approximately 10 A from the mutation site. In combination, these results indicate that solvation, structural plasticity and cooperative structural changes may play a role in ferritin function. Analogies with the structure and function of ion channel proteins such as annexins are noted.
About this Structure
1RCG is a Single protein structure of sequence from Rana catesbeiana with as ligand. Full crystallographic information is available from OCA.
Reference
High resolution crystal structures of amphibian red-cell L ferritin: potential roles for structural plasticity and solvation in function., Trikha J, Theil EC, Allewell NM, J Mol Biol. 1995 May 19;248(5):949-67. PMID:7760335
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