Characterization of XYN10B, a modular xylanase from the ruminal protozoan Polyplastron multivesiculatum, with a family 22 carbohydrate-binding module that binds to cellulose.
A new xylanase gene, xyn10B, was isolated from the ruminal protozoan Polyplastron multivesiculatum and the gene product was characterized. XYN10B is the first protozoan family 10 glycoside hydrolase characterized so far and is a modular enzyme comprising a family 22 carbohydrate-binding module (CBM) preceding the catalytic domain. The CBM22 was shown to be a true CBM. It showed high affinity for soluble arabinoxylan and is the first example of a CBM22 that binds strongly to celluloses of various crystallinities. The enzymic properties of XYN10B were also analysed. Its optimal temperature and pH for activity were 39 degrees C and 7.0 respectively; these values being close to those of the ruminal ecosystem. The phylogenetic relationships between the XYN10B CBM22 or catalytic domain and related sequences from ruminal and non-ruminal bacteria and eukaryotes are reported. The xyn10B gene is shown to lack introns.
Devillard
Estelle
E
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK.
Bera-Maillet
Christel
C
Flint
Harry J
HJ
Scott
Karen P
KP
Newbold
C James
CJ
Wallace
R John
RJ
Jouany
Jean-Pierre
JP
Forano
Evelyne
E
D000818:Animals; D015153:Blotting, Western; D020134:Catalytic Domain; D002482:Cellulose / Q000378:metabolism*; D016798:Ciliophora / Q000201:enzymology*; D003001:Cloning, Molecular; D003460:Crystallization; D017931:DNA Primers / Q000737:chemistry; D004269:DNA, Bacterial / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011134:Polysaccharides / Q000378:metabolism; D011485:Protein Binding; D015800:Protozoan Proteins / Q000378:metabolism*; D017384:Sequence Deletion; D013379:Substrate Specificity; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000378:metabolism*; D014995:Xylosidases / Q000378:metabolism*
D017931:DNA Primers; D004269:DNA, Bacterial; D011134:Polysaccharides; D015800:Protozoan Proteins; D014990:Xylans; D002482:Cellulose; D006026:Glycoside Hydrolases; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase