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PDBsum entry 1jz2
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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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A structural view of the action of escherichia coli (lacz) beta-Galactosidase.
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Authors
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D.H.Juers,
T.D.Heightman,
A.Vasella,
J.D.Mccarter,
L.Mackenzie,
S.G.Withers,
B.W.Matthews.
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Ref.
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Biochemistry, 2001,
40,
14781-14794.
[DOI no: ]
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PubMed id
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Abstract
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The structures of a series of complexes designed to mimic intermediates along
the reaction coordinate for beta-galactosidase are presented. These complexes
clarify and enhance previous proposals regarding the catalytic mechanism. The
nucleophile, Glu537, is seen to covalently bind to the galactosyl moiety. Of the
two potential acids, Mg(2+) and Glu461, the latter is in better position to
directly assist in leaving group departure, suggesting that the metal ion acts
in a secondary role. A sodium ion plays a part in substrate binding by directly
ligating the galactosyl 6-hydroxyl. The proposed reaction coordinate involves
the movement of the galactosyl moiety deep into the active site pocket. For
those ligands that do bind deeply there is an associated conformational change
in which residues within loop 794-804 move up to 10 A closer to the site of
binding. In some cases this can be inhibited by the binding of additional
ligands. The resulting restricted access to the intermediate helps to explain
why allolactose, the natural inducer for the lac operon, is the preferred
product of transglycosylation.
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Secondary reference #1
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Title
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High resolution refinement of beta-Galactosidase in a new crystal form reveals multiple metal-Binding sites and provides a structural basis for alpha-Complementation.
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Authors
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D.H.Juers,
R.H.Jacobson,
D.Wigley,
X.J.Zhang,
R.E.Huber,
D.E.Tronrud,
B.W.Matthews.
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Ref.
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Protein Sci, 2000,
9,
1685-1699.
[DOI no: ]
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PubMed id
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Secondary reference #2
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Title
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Structural comparisons of tim barrel proteins suggest functional and evolutionary relationships between beta-Galactosidase and other glycohydrolases.
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Authors
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D.H.Juers,
R.E.Huber,
B.W.Matthews.
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Ref.
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Protein Sci, 1999,
8,
122-136.
[DOI no: ]
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PubMed id
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Secondary reference #3
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Title
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Three-Dimensional structure of beta-Galactosidase from e. Coli.
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Authors
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R.H.Jacobson,
X.J.Zhang,
R.F.Dubose,
B.W.Matthews.
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Ref.
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Nature, 1994,
369,
761-766.
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PubMed id
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Secondary reference #4
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Title
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Crystallization of beta-Galactosidase from escherichia coli.
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Authors
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R.H.Jacobson,
B.W.Matthews.
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Ref.
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J Mol Biol, 1992,
223,
1177-1182.
[DOI no: ]
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PubMed id
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Figure 1.
Figure 1. Diffraction pattern of the monoclinic rystals recorded at CHESS. The inset shows an enlarged view of the
iffraction pattern aboe the beam stop. The cale is arked in millimeters. The blackening of the film to the left of the
beam stop is not due to misalignment but to he very igh intensity of the (0,0,6) reflection. 2'' oscillation photograph;
exposure time 2.5 min; rystal-to-film distance 400 mm; I = 0.908'' 8; film size 8 inches x 10 inches; crystal size
0% mm x 02 mm x @2 mm. The diffraction limit at thtop ad bottom edge of the film is 30 d.
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Figure 3.
Figure 3. Section = 180'' of the locked rotation fuction (Tong & Rossmann, 1990). Resolution 190 to 5.5 8. This
Figure displays the result of the calculation as a stereographic projection. The directions in space are plotted in spherical
polar co-ordinates where the axial tilt of the rotation vector away from the c axis of the crystal co-ordinate ystem ($) is
plotted latitudinaly and the rotation within the a*b* plane (4) longitudinally. The 3 crosses indicate 1 choice f a set f 3
orthogonal axes of Z-fold ymmetry (see the ext). Contours are drawn at increments of 1 with the lowest contour
drawn at 1.3 0 (see legend to Fig. 2).
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The above figures are
reproduced from the cited reference
with permission from Elsevier
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