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PDBsum entry 1v6y
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Structure and function of a family 10 beta-Xylanase chimera of streptomyces olivaceoviridis e-86 fxyn and cellulomonas fimi cex.
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Authors
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S.Kaneko,
H.Ichinose,
Z.Fujimoto,
A.Kuno,
K.Yura,
M.Go,
H.Mizuno,
I.Kusakabe,
H.Kobayashi.
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Ref.
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J Biol Chem, 2004,
279,
26619-26626.
[DOI no: ]
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PubMed id
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Abstract
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The catalytic domain of xylanases belonging to glycoside hydrolase family 10
(GH10) can be divided into 22 modules (M1 to M22; Sato, Y., Niimura, Y., Yura,
K., and Go, M. (1999) Gene (Amst.) 238, 93-101). Inspection of the crystal
structure of a GH10 xylanase from Streptomyces olivaceoviridis E-86 (SoXyn10A)
revealed that the catalytic domain of GH10 xylanases can be dissected into two
parts, an N-terminal larger region and C-terminal smaller region, by the
substrate binding cleft, corresponding to the module border between M14 and M15.
It has been suggested that the topology of the substrate binding clefts of GH10
xylanases are not conserved (Charnock, S. J., Spurway, T. D., Xie, H., Beylot,
M. H., Virden, R., Warren, R. A. J., Hazlewood, G. P., and Gilbert, H. J. (1998)
J. Biol. Chem. 273, 32187-32199). To facilitate a greater understanding of the
structure-function relationship of the substrate binding cleft of GH10
xylanases, a chimeric xylanase between SoXyn10A and Xyn10A from Cellulomonas
fimi (CfXyn10A) was constructed, and the topology of the hybrid substrate
binding cleft established. At the three-dimensional level, SoXyn10A and CfXyn10A
appear to possess 5 subsites, with the amino acid residues comprising subsites
-3 to +1 being well conserved, although the +2 subsites are quite different.
Biochemical analyses of the chimeric enzyme along with SoXyn10A and CfXyn10A
indicated that differences in the structure of subsite +2 influence bond
cleavage frequencies and the catalytic efficiency of xylooligosaccharide
hydrolysis. The hybrid enzyme constructed in this study displays fascinating
biochemistry, with an interesting combination of properties from the parent
enzymes, resulting in a low production of xylose.
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Figure 5.
FIG. 5. Bond cleavage frequencies of xylooligosaccharides
by CfXyn10A, SoXyn10A, and FC-14-15.
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Figure 7.
FIG. 7. HPAEC-PAD analysis of soluble birchwood xylan
hydrolysis by CfXyn10A, SoXyn10A, and FC-14-15. Birchwood xylan
hydrolysate by SoXyn10A (A), CfXyn10A (B), and FC-14-15 (C) were
applied to the HPAEC-PAD system. The positions at which xylose
(a), xylobiose (b), xylotriose (c), xylotetraose (d), and
xylooligosaccharides substituted by 4-O-methyl glucuronic acid
(e) were eluted from the HPAEC column are indicated.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2004,
279,
26619-26626)
copyright 2004.
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