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324 a.a.
Key reference
DOI no: 10.1002/prot.20700 Proteins 61:999 (2005) PubMed id: 16247799
Structural basis of the substrate subsite and the highly thermal stability of xylanase 10B from Thermotoga maritima MSB8. Ihsanawati, T.Kumasaka, T.Kaneko, C.Morokuma, R.Yatsunami, T.Sato, S.Nakamura, N.Tanaka. ABSTRACT
The crystal structure of xylanase 10B from Thermotoga maritima MSB8 (TmxB), a hyperthermostable xylanase, has been solved in its native form and in complex with xylobiose or xylotriose at 1.8 A resolution. In order to gain insight into the substrate subsite and the molecular features for thermal stability, we compared TmxB with family 10 xylanase structures from nine microorganisms. As expected, TmxB folds into a (beta/alpha)8-barrel structure, which is common among the glycoside hydrolase family 10. The enzyme active site and the environment surrounding the xylooligosaccharide of TmxB are highly similar to those of family 10 xylanases. However, only two xylose moieties were found in its binding pocket from the TmxB-xylotriose complex structure. This finding suggests that TmxB could be a potential biocatalyst for the large-scale production of xylobiose. The result of structural analyses also indicated that TmxB possesses some additional features that account for its thermostability. In particular, clusters of aromatic residues together with a lack of exposed hydrophobic residues are characteristic of the TmxB structure. TmxB has also a significant number of ion pairs on the protein surface that are not found in other thermophilic family 10 xylanases.
Selected figure(s)
Figure 1.
Figure 1. A: Overall structure of TmxB (in stereo) from the top view. Major-helices and
-strands are drawn in red and green, respectively, and labeled according to the ideal (
Figure 4.
Figure 4. Molecular interactions for thermal stability of TmxB. A: Aromatic interactions from the top view showing five distinct clusters drawn in different colors. B: Electrostatic interactions in the C-terminal region consist of a triad salt bridge (Asp780-Asp784-Lys836) and single ones (Lys769-Glu773, Asp798-Lys823 and Lys835-Glu839. C-E: Comparison of aromatic interactions, connectingThe above figures are reprinted by permission from John Wiley & Sons, Inc.: Proteins (2005, 61, 999-0) copyright 2005. Figures were selected by an automated process.
Literature references that cite this PDB file's key reference
PubMed id Reference
18725971 A.Bharadwaj, S.Leelavathi, S.Mazumdar-Leighton, A.Ghosh, S.Ramakumar, and V.S.Reddy (2008).
The critical role of partially exposed N-terminal valine residue in stabilizing GH10 xylanase from Bacillus sp.NG-27 under poly-extreme conditions.PLoS ONE, 3, e3063.
16823036 K.Manikandan, A.Bhardwaj, N.Gupta, N.K.Lokanath, A.Ghosh, V.S.Reddy, and S.Ramakumar (2006).
Crystal structures of native and xylosaccharide-bound alkali thermostable xylanase from an alkalophilic Bacillus sp. NG-27: structural insights into alkalophilicity and implications for adaptation to polyextreme conditions.Protein Sci, 15, 1951-1960.
PDB codes: 2f8q 2fgl The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB codes are shown on the right.
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