Characterization of thermostable Xyn10A enzyme from mesophilic Clostridium acetobutylicum ATCC 824.
A thermostable xylanase gene, xyn10A (CAP0053), was cloned from Clostridium acetobutylicum ATCC 824. The nucleotide sequence of the C. acetobutylicum xyn10A gene encoded a 318-amino-acid, single-domain, family 10 xylanase, Xyn10A, with a molecular mass of 34 kDa. Xyn10A exhibited extremely high (92%) amino acid sequence identity with Xyn10B (CAP0116) of this strain and had 42% and 32% identity with the catalytic domains of Rhodothermus marinus xylanase I and Thermoascus aurantiacus xylanase I, respectively. Xyn10A enzyme was purified from recombinant Escherichia coli and was highly active toward oat-spelt and Birchwood xylan and slightly active toward carboxymethyl cellulose, arabinogalactouronic acid, and various p-nitrophenyl monosaccharides. Xyn10A hydrolyzed xylan and xylooligosaccharides larger than xylobiose to produce xylose. This enzyme was optimally active at 60 degrees C and had an optimum pH of 5.0. This is one of a number of related activities encoded on the large plasmid in this strain.
Ali
Mursheda K
MK
Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA.
Rudolph
Frederick B
FB
Bennett
George N
GN
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D046969:Clostridium acetobutylicum / Q000201:enzymology* / Q000235:genetics*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics; D043325:Xylan Endo-1,3-beta-Xylosidase / Q000235:genetics* / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism
D011994:Recombinant Proteins; D014994:Xylose; D043325:Xylan Endo-1,3-beta-Xylosidase