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PDBsum entry 1tqh
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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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Covalent reaction intermediate revealed in crystal structure of the geobacillus stearothermophilus carboxylesterase est30.
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Authors
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P.Liu,
Y.F.Wang,
H.E.Ewis,
A.T.Abdelal,
C.D.Lu,
R.W.Harrison,
I.T.Weber.
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Ref.
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J Mol Biol, 2004,
342,
551-561.
[DOI no: ]
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PubMed id
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Abstract
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Est30 is a thermophilic carboxylesterase cloned from Geobacillus
stearothermophilus that showed optimal hydrolysis of esters with short acyl
chains at 70 degrees C. Est30 is a member of a new family of carboxylesterases
with representatives in other Gram-positive bacteria. The crystal structure has
been determined at 1.63A resolution using multiple anomalous dispersion data.
The two-domain crystal structure showed a large domain with a modified
alpha/beta hydrolase core including a seven, rather than an eight-stranded beta
sheet, and a smaller cap domain comprising three alpha helices. The catalytic
triad consists of residues Ser94, Asp193, and His223. A 100Da tetrahedral ligand
was observed to be covalently bound to the side-chain of Ser94. The propyl
acetate ligand represents the first tetrahedral intermediate in the reaction
mechanism. Therefore, this Est30 crystal structure will help understand the mode
of action of all enzymes in the serine hydrolase superfamily.
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Figure 2.
Figure 2. The active site region of
Est30. (a) 2FoKFc electron density
map contoured at 1.6s. (b) Inter-
acting residues. Interatomic inter-
actions are shown in broken lines
with distances in Å . The negative
charge of the oxygen atom of the
tetrahedral intermediate and the
NH groups of Leu95 and Phe25
form an oxyanion hole (labeled in
red).
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The above figure is
reprinted
by permission from Elsevier:
J Mol Biol
(2004,
342,
551-561)
copyright 2004.
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