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PDBsum entry 1rcc
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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 amphibian red-Cell l ferritin: potential roles for structural plasticity and solvation in function.
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Authors
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J.Trikha,
E.C.Theil,
N.M.Allewell.
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Ref.
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J Mol Biol, 1995,
248,
949-967.
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PubMed id
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Abstract
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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.
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Secondary reference #1
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Title
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Crystallization and structural analysis of bullfrog red cell l-Subunit ferritins.
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Authors
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J.Trikha,
G.S.Waldo,
F.A.Lewandowski,
Y.Ha,
E.C.Theil,
P.C.Weber,
N.M.Allewell.
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Ref.
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Proteins, 1994,
18,
107-118.
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PubMed id
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