1clx
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CATALYTIC CORE OF XYLANASE A
OverviewOverview
The three-dimensional structure of native xylanase A from Pseudomonas, flouorescens subspecies cellulosa has been refined at 1.8 A resolution., The space group is P2(1)2(1)2(1) with four molecules in the asymmetric, unit. The final model has an R factor of 0.166 for 103 749 reflections, with the four molecules refined independently. The tertiary structure, consists of an eightfold beta/alpha-barrel, the so-called TIM-barrel fold., The active site is in an open cleft at the carboxy-terminal end of the, beta/alpha-barrel, and the active-site residues are a pair of glutamates, Glu127 on strand 4 and Glu246 on strand 7. Both these catalytic glutamate, residues are found on beta-bulges. An atypically long loop after strand 7, is stabilized by calcium. Unusual features include a non-proline, cis-peptide residue Ala80 which is found on a beta-bulge at the end of, beta-strand 3. The three beta-bulge type distortions occurring on, beta-strands 3, 4 and 7 are functionally significant as they serve to, orient important active-site residues. The active-site residues are, further held in place by an extensive hydrogen-bonding network of, active-site residues in the catalytic site of xylanase A. A chain of well, ordered water molecules occupies the substrate-binding cleft, some or all, of which are expelled on binding of the substrate.
About this StructureAbout this Structure
1CLX is a Single protein structure of sequence from Cellvibrio japonicus with CA as ligand. Active as Endo-1,4-beta-xylanase, with EC number 3.2.1.8 Structure known Active Site: CAT. Full crystallographic information is available from OCA.
ReferenceReference
Refined crystal structure of the catalytic domain of xylanase A from Pseudomonas fluorescens at 1.8 A resolution., Harris GW, Jenkins JA, Connerton I, Pickersgill RW, Acta Crystallogr D Biol Crystallogr. 1996 Mar 1;52(Pt 2):393-401. PMID:15299710
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