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PDBsum entry 2fgl
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Contents |
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* Residue conservation analysis
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Enzyme class:
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E.C.3.2.1.8
- endo-1,4-beta-xylanase.
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Reaction:
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Endohydrolysis of 1,4-beta-D-xylosidic linkages in xylans.
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DOI no:
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Protein Sci
15:1951-1960
(2006)
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PubMed id:
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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.
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K.Manikandan,
A.Bhardwaj,
N.Gupta,
N.K.Lokanath,
A.Ghosh,
V.S.Reddy,
S.Ramakumar.
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ABSTRACT
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Crystal structures are known for several glycosyl hydrolase family 10 (GH10)
xylanases. However, none of them is from an alkalophilic organism that can grow
in alkaline conditions. We have determined the crystal structures at 2.2
Angstroms of a GH10 extracellular endoxylanase (BSX) from an alkalophilic
Bacillus sp. NG-27, for the native and the complex enzyme with xylosaccharides.
The industrially important enzyme is optimally active and stable at 343 K and at
a pH of 8.4. Comparison of the structure of BSX with those of other thermostable
GH10 xylanases optimally active at acidic or close to neutral pH showed that the
solvent-exposed acidic amino acids, Asp and Glu, are markedly enhanced in BSX,
while solvent-exposed Asn was noticeably depleted. The BSX crystal structure
when compared with putative three-dimensional homology models of other
extracellular alkalophilic GH10 xylanases from alkalophilic organisms suggests
that a protein surface rich in acidic residues may be an important feature
common to these alkali thermostable enzymes. A comparison of the surface
features of BSX and of halophilic proteins allowed us to predict the activity of
BSX at high salt concentrations, which we verified through experiments. This
offered us important lessons in the polyextremophilicity of proteins, where
understanding the structural features of a protein stable in one set of extreme
conditions provided clues about the activity of the protein in other extreme
conditions. The work brings to the fore the role of the nature and composition
of solvent-exposed residues in the adaptation of enzymes to polyextreme
conditions, as in BSX.
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Literature references that cite this PDB file's key reference
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PubMed id
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Reference
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Y.Zhao,
Y.Zhang,
Y.Cao,
J.Qi,
L.Mao,
Y.Xue,
F.Gao,
H.Peng,
X.Wang,
G.F.Gao,
and
Y.Ma
(2011).
Structural analysis of alkaline β-mannanase from alkaliphilic Bacillus sp. N16-5: implications for adaptation to alkaline conditions.
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PLoS One,
6,
e14608.
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A.Bhardwaj,
S.Leelavathi,
S.Mazumdar-Leighton,
A.Ghosh,
S.Ramakumar,
and
V.S.Reddy
(2010).
The critical role of N- and C-terminal contact in protein stability and folding of a family 10 xylanase under extreme conditions.
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PLoS One,
5,
e11347.
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G.Zhang,
L.Mao,
Y.Zhao,
Y.Xue,
and
Y.Ma
(2010).
Characterization of a thermostable xylanase from an alkaliphilic Bacillus sp.
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Biotechnol Lett,
32,
1915-1920.
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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.
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PLoS ONE,
3,
e3063.
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L.P.Wackett
(2008).
Biomass to fuels via microbial transformations.
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Curr Opin Chem Biol,
12,
187-193.
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V.Solomon,
A.Teplitsky,
S.Shulami,
G.Zolotnitsky,
Y.Shoham,
and
G.Shoham
(2007).
Structure-specificity relationships of an intracellular xylanase from Geobacillus stearothermophilus.
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Acta Crystallogr D Biol Crystallogr,
63,
845-859.
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PDB code:
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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
code is
shown on the right.
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Links
