1H1A

Thermophilic beta-1,4-xylanase from Chaetomium thermophilum

Summary for 1H1A

• Entry DOI: 10.2210/pdb1h1a/pdb
• Descriptor: Endo-1,4-beta-xylanase, UNKNOWN ATOM OR ION, SULFATE ION, ... (6 entities in total)
• Functional Keywords: hydrolase, xylanase, glycosyl hydrolase, family 11, thermostability glycosidase
• Biological source: Chaetomium thermophilum
• Total number of polymer chains: 2
• Total formula weight: 42505.72

Authors

Hakulinen, N.,Rouvinen, J. (deposition date: 2002-07-05, release date: 2003-07-04, Last modification date: 2024-11-06)

Primary citation

Hakulinen, N.,Turunen, O.,Janis, J.,Leisola, M.,Rouvinen, J.
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.
Eur.J.Biochem., 270:1399-1412, 2003

PubMed Abstract: 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.

PubMed: 12653995
DOI: 10.1046/J.1432-1033.2003.03496.X

Experimental method

X-RAY DIFFRACTION (1.75 Å)