1exp

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==Overview==
==Overview==
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The three-dimensional structure of a catalytically competent, glycosyl-enzyme intermediate of a retaining beta-1,4-glycanase has been, determined at a resolution of 1.8 A by X-ray diffraction. A fluorinated, slow substrate forms an alpha-D-glycopyranosyl linkage to one of the two, invariant carboxylates, Glu 233, as supported in solution by 19F-NMR, studies. The resulting ester linkage is coplanar with the cyclic oxygen of, the proximal saccharide and is inferred to form a strong hydrogen bond, with the 2-hydroxyl of that saccharide unit in natural substrates. The, active-site architecture of this covalent intermediate gives insights into, both the classical double-displacement catalytic mechanism and the basis, for the enzyme's specificity.
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The three-dimensional structure of a catalytically competent glycosyl-enzyme intermediate of a retaining beta-1,4-glycanase has been determined at a resolution of 1.8 A by X-ray diffraction. A fluorinated slow substrate forms an alpha-D-glycopyranosyl linkage to one of the two invariant carboxylates, Glu 233, as supported in solution by 19F-NMR studies. The resulting ester linkage is coplanar with the cyclic oxygen of the proximal saccharide and is inferred to form a strong hydrogen bond with the 2-hydroxyl of that saccharide unit in natural substrates. The active-site architecture of this covalent intermediate gives insights into both the classical double-displacement catalytic mechanism and the basis for the enzyme's specificity.
==About this Structure==
==About this Structure==
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[[Category: Cellulomonas fimi]]
[[Category: Cellulomonas fimi]]
[[Category: Single protein]]
[[Category: Single protein]]
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[[Category: Johns, K.L.]]
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[[Category: Johns, K L.]]
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[[Category: Rose, D.R.]]
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[[Category: Rose, D R.]]
[[Category: Tull, D.]]
[[Category: Tull, D.]]
[[Category: White, A.]]
[[Category: White, A.]]
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[[Category: Withers, S.G.]]
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[[Category: Withers, S G.]]
[[Category: cellulose degradation]]
[[Category: cellulose degradation]]
[[Category: glycosidase]]
[[Category: glycosidase]]
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[[Category: signal]]
[[Category: signal]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb 3 09:39:34 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:32:36 2008''

Revision as of 10:32, 21 February 2008


1exp, resolution 1.8Å

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BETA-1,4-GLYCANASE CEX-CD

Overview

The three-dimensional structure of a catalytically competent glycosyl-enzyme intermediate of a retaining beta-1,4-glycanase has been determined at a resolution of 1.8 A by X-ray diffraction. A fluorinated slow substrate forms an alpha-D-glycopyranosyl linkage to one of the two invariant carboxylates, Glu 233, as supported in solution by 19F-NMR studies. The resulting ester linkage is coplanar with the cyclic oxygen of the proximal saccharide and is inferred to form a strong hydrogen bond with the 2-hydroxyl of that saccharide unit in natural substrates. The active-site architecture of this covalent intermediate gives insights into both the classical double-displacement catalytic mechanism and the basis for the enzyme's specificity.

About this Structure

1EXP is a Single protein structure of sequence from Cellulomonas fimi. Known structural/functional Sites: and . Full crystallographic information is available from OCA.

Reference

Crystallographic observation of a covalent catalytic intermediate in a beta-glycosidase., White A, Tull D, Johns K, Withers SG, Rose DR, Nat Struct Biol. 1996 Feb;3(2):149-54. PMID:8564541

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