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PDBsum entry 1so9
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Metal transport
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PDB id
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1so9
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Contents |
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* Residue conservation analysis
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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 cox11, A novel type of beta-Immunoglobulin-Like fold involved in cub site formation of cytochrome c oxidase.
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Authors
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L.Banci,
I.Bertini,
F.Cantini,
S.Ciofi-Baffoni,
L.Gonnelli,
S.Mangani.
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Ref.
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J Biol Chem, 2004,
279,
34833-34839.
[DOI no: ]
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PubMed id
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Abstract
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Cytochrome c oxidase assembly process involves many accessory proteins including
Cox11, which is a copper-binding protein required for Cu incorporation into the
Cu(B) site of cytochrome c oxidase. In a genome wide search, a number of Cox11
homologs are found in all of the eukaryotes with complete genomes and in several
Gram-negative bacteria. All of them possess a highly homologous soluble domain
and contain an N-terminal fragment that anchors the protein to the membrane. An
anchor-free construct of 164 amino acids was obtained from Sinorhizobium
meliloti, and the first structure of this class of proteins is reported here.
The apoform has an immunoglobulin-like fold with a novel type of beta-strand
organization. The copper binding motif composed of two highly conserved
cysteines is located on one side of the beta-barrel structure. The apoprotein is
monomeric in the presence of dithiothreitol, whereas it dimerizes in the absence
of the reductant. When copper(I) binds, NMR and extended x-ray absorption fine
structure (EXAFS) data indicate a dimeric protein state with two thiolates
bridging two copper(I) ions. The present results advance the knowledge on the
poorly understood molecular aspects of cytochrome c oxidase assembly.
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Figure 1.
FIG. 1. Solution structure of apoCox11 (residues 20-151).
The radius of the tube is proportional to the backbone root mean
square deviation of each residue. The secondary structure
elements are shown (  -strands in gray and
helices in black). The two black spheres indicate the sulfur
atoms of Cys-100 and Cys-102, whereas the white sphere
represents the N  of Lys-97.
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Figure 3.
FIG. 3. Comparison between the structures and the
two-dimensional topology of apoCox11 (A), a linker domain of a
bacterial sialidase (Protein Data Bank code 1eut [PDB]
) (B), and a motile major sperm protein of A. suum (Protein Data
Bank code 1msp [PDB]
) (C). The side chains of the Cys-100 and Cys-102 are indicated.
The dashed lines indicate sheet formation between two -strands.
-Strands a, b, c, e, f,
and g (colored gray) are common to all of the Ig-like domains.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2004,
279,
34833-34839)
copyright 2004.
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