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PDBsum entry 1vfi
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Metal binding protein
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PDB id
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1vfi
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References listed in PDB file
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Key reference
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Title
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Solution structure of vanabin2, A vanadium(IV)-Binding protein from the vanadium-Rich ascidian ascidia sydneiensis samea.
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Authors
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T.Hamada,
M.Asanuma,
T.Ueki,
F.Hayashi,
N.Kobayashi,
S.Yokoyama,
H.Michibata,
H.Hirota.
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Ref.
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J Am Chem Soc, 2005,
127,
4216-4222.
[DOI no: ]
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PubMed id
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Abstract
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Ascidians belonging to the suborder Phlebobranchia are known to accumulate high
levels of a transition metal, vanadium, in their blood cells, called
vanadocytes, although the mechanism for this biological phenomenon remains
unclear. Recently, we identified vanadium(IV)-binding proteins, designated as
Vanabins, from vanadium-accumulating ascidians. Here, we report the first 3D
structure of Vanabin2 from an ascidian, Ascidia sydneiensis samea, in an aqueous
solution. The structure revealed a novel bow-shaped conformation, with four
alpha-helices connected by nine disulfide bonds. There are no structural
homologues reported so far. The 15N heteronuclear single-quantum coherence
(HSQC) perturbation experiments of Vanabin2 indicated that vanadyl cations,
which are exclusively localized on the same face of the molecule, are
coordinated by amine nitrogens derived from amino acid residues such as lysines,
arginines, and histidines, as suggested by the electron paramagnetic resonance
(EPR) results. The present NMR studies provide information that will contribute
toward elucidating the mechanism of vanadium accumulation in ascidians.
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