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PDBsum entry 1e65
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Electron transport
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PDB id
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1e65
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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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Crystal structure of pseudomonas aeruginosa apo-Azurin at 1.85 a resolution.
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Authors
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H.Nar,
A.Messerschmidt,
R.Huber,
M.Van de kamp,
G.W.Canters.
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Ref.
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Febs Lett, 1992,
306,
119-124.
[DOI no: ]
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PubMed id
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Abstract
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The 3D structure of apo-azurin from Pseudomonas aeruginosa has been determined
at 1.85 A resolution. The crystal structure is composed of two different
molecular forms of apo-azurin arranged as hetero-dimers in the tetramer of the
asymmetric unit. Form 1 closely resembles the holo-protein lacking copper. Form
2 shows differences in the metal binding site region induced by the
incorporation of a solvent molecule into this site. The positions of the copper
ligands His46 and His117 are shifted by 0.6 A and 1.6 A. The His117 side chain
adopts a position at the surface of the protein, thereby facilitating access to
the copper site. The presence of two different molecular forms of apo-azurin in
the crystal lattice may reflect an equilibrium between the two forms in
solution. 1H-NMR spectra of apo-azurin recorded as a function of pH show that at
high pH the line broadening of His35, His46 and His117 resonances is consistent
with an interconversion between forms 1 and 2. At low pH, no broadening is
observed. This may indicate that here the interconversion is fast on the NMR
timescale.
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Figure 2.
Fig. 2. Superposition of apo.azurin form 1 (monomer . thick lines) on Cull I) azurin (thin lines). Apart from the absence of the metal and a minor
shift of the His 7 side cllaita toward the c~wity, the :ttomic rnodels are indisting.aishable.
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Figure 4.
Fig. 4. Superposition ofapo-azuin form 2 (monomer D, thick lines) on Cu(ll) azurin thin lines). Differences between the two structures are entred
at l-lis 4~ nd His j iv, The side chain of His = 7 is shlrtcd by 1.6 toward the protein urface without changig the orientation of the imidazole ring.
The surface water molecule bou,ad to His = ~7 Ne shifts accordingly. Movement of Met ~ and Phe t~a side chaiqs prvides the space necessary for the
His ~7 swinging motion, The His 4~ side chain is moved in the opposite direction (0,6 A). This shift results in a slight positionl adjustment (0.4 A)
f the adjacent main chain of residues 8 to 10.
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The above figures are
reprinted
by permission from the Federation of European Biochemical Societies:
Febs Lett
(1992,
306,
119-124)
copyright 1992.
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Secondary reference #1
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Title
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Crystal structure analysis of oxidized pseudomonas aeruginosa azurin at ph 5.5 and ph 9.0. A ph-Induced conformational transition involves a peptide bond flip.
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Authors
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H.Nar,
A.Messerschmidt,
R.Huber,
M.Van de kamp,
G.W.Canters.
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Ref.
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J Mol Biol, 1991,
221,
765-772.
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PubMed id
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