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PDBsum entry 1eog
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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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Structures of thermolabile mutants of human glutathione transferase p1-1.
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Authors
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J.Rossjohn,
W.J.Mckinstry,
A.J.Oakley,
M.W.Parker,
G.Stenberg,
B.Mannervik,
B.Dragani,
R.Cocco,
A.Aceto.
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Ref.
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J Mol Biol, 2000,
302,
295-302.
[DOI no: ]
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PubMed id
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Abstract
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An N-capping box motif (Ser/Thr-Xaa-Xaa-Asp) is strictly conserved at the
beginning of helix alpha6 in the core of virtually all glutathione transferases
(GST) and GST-related proteins. It has been demonstrated that this local motif
is important in determining the alpha-helical propensity of the isolated
alpha6-peptide and plays a crucial role in the folding and stability of GSTs.
Its removal by site-directed mutagenesis generated temperature-sensitive folding
mutants unable to refold at physiological temperature (37 degrees C). In the
present work, variants of human GSTP1-1 (S150A and D153A), in which the capping
residues have been substituted by alanine, have been generated and purified for
structural analysis. Thus, for the first time, temperature-sensitive folding
mutants of an enzyme, expressed at a permissive temperature, have been
crystallized and their three-dimensional structures determined by X-ray
crystallography. The crystal structures of human pi class GST
temperature-sensitive mutants provide a basis for understanding the structural
origin of the dramatic effects observed on the overall stability of the enzyme
at higher temperatures upon single substitution of a capping residue.
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Figure 1.
Figure 1. Ribbon picture of a monomer of human pi class
GST. The location of helix a6, the GST motif II (the conserved
sequence motif consisting of helix a6 and the preceding long
loop), GSH and the sites of mutation (shown in ball-and-stick)
are indicated. This Figure was produced using MOLSCRIPT [Kraulis
1991].
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Figure 2.
Figure 2. Stereoviews of the region in GST P1-1 about the
sites of mutation. The N-terminal end of helix a6 is shown in
ribbon representation and key residues are shown as
ball-and-stick. (a) Wild-type structure (9GSS; [Oakley et al
1997]), (b) S150A and (c) D153A. The Figure was produced using
MOLSCRIPT [Kraulis 1991].
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2000,
302,
295-302)
copyright 2000.
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