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Title
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Crystal structure analysis and refinement at 2.15 A resolution of amicyanin, a type I blue copper protein, from Thiobacillus versutus.
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Authors
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A.Romero,
H.Nar,
R.Huber,
A.Messerschmidt,
A.P.Kalverda,
G.W.Canters,
R.Durley,
F.S.Mathews.
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Ref.
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J Mol Biol, 1994,
236,
1196-1211.
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PubMed id
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Abstract
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The crystal structure of the type I blue copper protein amicyanin from
Thiobacillus versutus has been determined by Patterson search techniques on the
basis of the molecular model of amicyanin from Paracoccus denitrificans, and
refined by energy-restrained least-squares methods. Amicyanin crystallizes in
the trigonal space group P3(2) with unit cell dimensions of a = b = 87.40 A, c =
38.20 A. The asymmetric unit is composed of three independent molecules centred
on the crystallographic 3(2) axes. The final R-value is 17.4% for 15,984
reflections to a resolution of 2.15 A. The polypeptide fold in amicyanin is
based on the beta-sandwich structure commonly found in blue copper proteins.
Nine beta strands are folded into two twisted beta-sheets that pack together
with a filling of non-polar residues between them. The geometry of the copper
site is similar to that of plastocyanin. There are four ligands, arranged
approximately as a distorted tetrahedron, to the copper atom: His54, Cys93,
His96 and Met99. One of the copper ligands, His96, is exposed to the surface and
lies in the centre of a cluster of seven hydrophobic residues.
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