Overproduction and characterization of seleno-methionine xylanase T-6.
The extracellular xylanase from Bacillus stearothermophilus T-6 is a thermostable alkaline tolerant enzyme that was found to bleach pulp optimally at pH 9 and 65 degrees C, and was successfully used in a large-scale bio-bleaching mill trial. In an attempt to obtain a heavy atom derivative suitable for complete X-ray analysis, xylanase T-6 was labeled biosynthetically with seleno-methionine, resulting in a 'built-in' array of atoms with specific X-ray anomalous scattering signal. Optimization of growth conditions resulted in over 0.8 g of homogeneous seleno-methionine xylanase T-6 per liter culture. The seleno-methionine enzyme was shown to be fully active and produced single crystals suitable for complete multiple wavelength anomalous diffraction (MAD) structural analysis.
Mechaly
A
A
Department of Food Engineering and Biotechnology, Technion, Haifa, Israel.
Teplitsky
A
A
Belakhov
V
V
Baasov
T
T
Shoham
G
G
Shoham
Y
Y
D001709:Biotechnology / Q000379:methods; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D001411:Geobacillus stearothermophilus / Q000201:enzymology*; D010209:Paper; D012645:Selenomethionine / Q000378:metabolism*; D013329:Structure-Activity Relationship; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000096:biosynthesis* / Q000737:chemistry*
D012645:Selenomethionine; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase