1exp | pdb_00001exp
BETA-1,4-GLYCANASE CEX-CD
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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]. 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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