1h1a
From Proteopedia
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==Overview== | ==Overview== | ||
| - | The crystal structures of thermophilic xylanases from Chaetomium | + | The crystal structures of thermophilic xylanases from Chaetomium thermophilum and Nonomuraea flexuosa were determined at 1.75 and 2.1 A resolution, respectively. Both enzymes have the overall fold typical to family 11 xylanases with two highly twisted beta-sheets forming a large cleft. The comparison of 12 crystal structures of family 11 xylanases from both mesophilic and thermophilic organisms showed that the structures of different xylanases are very similar. The sequence identity differences correlated well with the structural differences. Several minor modifications appeared to be responsible for the increased thermal stability of family 11 xylanases: (a) higher Thr : Ser ratio (b) increased number of charged residues, especially Arg, resulting in enhanced polar interactions, and (c) improved stabilization of secondary structures involved the higher number of residues in the beta-strands and stabilization of the alpha-helix region. Some members of family 11 xylanases have a unique strategy to improve their stability, such as a higher number of ion pairs or aromatic residues on protein surface, a more compact structure, a tighter packing, and insertions at some regions resulting in enhanced interactions. |
==About this Structure== | ==About this Structure== | ||
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[[Category: xylanase]] | [[Category: xylanase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:56:22 2008'' |
Revision as of 10:56, 21 February 2008
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THERMOPHILIC B-1,4-XYLANASE FROM CHAETOMIUM THERMOPHILUM
Overview
The crystal structures of thermophilic xylanases from Chaetomium thermophilum and Nonomuraea flexuosa were determined at 1.75 and 2.1 A resolution, respectively. Both enzymes have the overall fold typical to family 11 xylanases with two highly twisted beta-sheets forming a large cleft. The comparison of 12 crystal structures of family 11 xylanases from both mesophilic and thermophilic organisms showed that the structures of different xylanases are very similar. The sequence identity differences correlated well with the structural differences. Several minor modifications appeared to be responsible for the increased thermal stability of family 11 xylanases: (a) higher Thr : Ser ratio (b) increased number of charged residues, especially Arg, resulting in enhanced polar interactions, and (c) improved stabilization of secondary structures involved the higher number of residues in the beta-strands and stabilization of the alpha-helix region. Some members of family 11 xylanases have a unique strategy to improve their stability, such as a higher number of ion pairs or aromatic residues on protein surface, a more compact structure, a tighter packing, and insertions at some regions resulting in enhanced interactions.
About this Structure
1H1A is a Single protein structure of sequence from Chaetomium thermophilum with , , and as ligands. Active as Endo-1,4-beta-xylanase, with EC number 3.2.1.8 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Three-dimensional structures of thermophilic beta-1,4-xylanases from Chaetomium thermophilum and Nonomuraea flexuosa. Comparison of twelve xylanases in relation to their thermal stability., Hakulinen N, Turunen O, Janis J, Leisola M, Rouvinen J, Eur J Biochem. 2003 Apr;270(7):1399-412. PMID:12653995
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