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PDBsum entry 1tml
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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 the catalytic domain of a thermophilic endocellulase.
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Authors
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M.Spezio,
D.B.Wilson,
P.A.Karplus.
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Ref.
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Biochemistry, 1993,
32,
9906-9916.
[DOI no: ]
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PubMed id
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Abstract
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One way to improve the economic feasibility of biomass conversion is to enhance
the catalytic efficiency of cellulases through protein engineering. This
requires that high-resolution structures of cellulases be available. Here we
present the structure of E2cd, the catalytic domain of the thermophilic
endocellulase E2 from Thermomonospora fusca, as determined by X-ray
crystallography. The structure was solved by multiple isomorphous replacement at
2.6-A resolution and has been refined at 1.8-A resolution to an R-value of 18.4%
for all reflections between 10- and 1.8-A resolution. The fold of E2cd is based
on an unusual parallel beta-barrel and is equivalent to the fold determined for
the catalytic domain of cellobiohydrolase II, an exocellulase from Trichoderma
reesei [Rouvinen et al. (1990) Science 249, 380-385]. The active site cleft of
the enzyme, approximately 11 A deep and running the entire length of the
molecule, is seen to be completely free for ligand binding in the crystal. A
2.2-A resolution analysis of crystals of E2cd complexed with cellobiose, an
inhibitor, shows how cellobiose binds in the active site and interacts with
several residues which line the cleft. Catalytic roles are suggested for three
aspartic acid residues at the active site. A comparison of the E2cd and CBHIIcd
structures reveals a large difference in their active site accessibilities and
supports the hypothesis that the main difference between endo- and exocellulases
is the degree to which their active sites are accessible to substrate.
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Secondary reference #1
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Title
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Crystal structure of the catalytic domain of a thermophilic endocellulase.
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Authors
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M.Spezio,
D.B.Wilson,
P.A.Karplus.
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Ref.
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Biochemistry, 1993,
32,
9906-9916.
[DOI no: ]
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PubMed id
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Note: In the PDB file this reference is
annotated as "TO BE PUBLISHED". The citation details given above have
been manually determined.
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