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PDBsum entry 1gn2
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Oxidoreductase
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PDB id
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1gn2
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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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Engineering of an intersubunit disulfide bridge in the iron-Superoxide dismutase of mycobacterium tuberculosis.
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Authors
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K.A.Bunting,
J.B.Cooper,
I.J.Tickle,
D.B.Young.
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Ref.
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Arch Biochem Biophys, 2002,
397,
69-76.
[DOI no: ]
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PubMed id
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Abstract
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With the aim of enhancing interactions involved in dimer formation, an
intersubunit disulfide bridge was engineered in the superoxide dismutase enzyme
of Mycobacterium tuberculosis. Ser-123 was chosen for mutation to cysteine since
it resides at the dimer interface where the serine side chain interacts with the
same residue in the opposite subunit. Gel electrophoresis and X-ray
crystallographic studies of the expressed mutant confirmed formation of the
disulfide bond under nonreducing conditions. However, the mutant protein was
found to be less stable than the wild type as judged by susceptibility to
denaturation in the presence of guanidine hydrochloride. Decreased stability
probably results from formation of a disulfide bridge with a suboptimal torsion
angle and exclusion of solvent molecules from the dimer interface.
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Secondary reference #1
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Title
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Engineering a change in metal-Ion specificity of the iron-Dependent superoxide dismutase from mycobacterium tuberculosis-- X-Ray structure analysis of site-Directed mutants.
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Authors
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K.Bunting,
J.B.Cooper,
M.O.Badasso,
I.J.Tickle,
M.Newton,
S.P.Wood,
Y.Zhang,
D.Young.
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Ref.
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Eur J Biochem, 1998,
251,
795-803.
[DOI no: ]
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PubMed id
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Figure 4.
Fig. 4. The electron density (2FO -FC ) contours for the active site in the H145Q mutant structure. The Gln145 side chain is on the right hand
side. It has refined to a conformation in which it forms interactions similar to those found in other SOD structures possessing glutamine at this
position. The low resolution of the data do not justify inclusion of the active site solvent molecule which is normally located between the metal ion
and residue
145.
The map is contoured at
1.0
rms.
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Figure 5.
Fig. 5. The electron density (2F O -F C) contours for the active site residues in the H145E mutant structure. The resolution of the map is 2.5 A
š
and contours at the 1.0 rms level are shown. Glu145 is on the right. SOLV indicates the putative hydroxide ion ligand.
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The above figures are
reproduced from the cited reference
with permission from the Federation of European Biochemical Societies
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