Evidence for a general role for non-catalytic thermostabilizing domains in xylanases from thermophilic bacteria.
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Cloned and characterized xynY gene from C. thermocellum
"A genomic library of Clostridium thermocellum DNA constructed in lambda ZAPII was screened for xylanase-expressing clones. Cross-hybridization experiments revealed a new xylanase gene isolated from the gene library, which was designated xyn Y."
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Demonstrated endo-beta-1,4-xylanase activity on oat spelt, wheat and rye arabinoxylans
"The encoded enzyme, xylanase Y (XYLY), displayed features characteristic of an endo-beta1,4-xylanase: the enzyme rapidly hydrolysed oat spelt, wheat and rye arabinoxylans and was active against methyl-umbelliferyl-beta-D-cellobioside, but did not hydrolyse any cellulosic substrates."
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Identified signal peptide, catalytic domain, thermostable domain, and dockerin docking sequence
"The encoded enzyme contained a typical N-terminal 26-residue signal peptide, followed by a 164 amino acid sequence, designated domain A, that was not essential for catalytic activity."
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Western blot confirmed localization of XynY to the cellulosome
"Western blot analysis using antiserum raised against XYLY showed that the xylanase was located in the cellulosome and did not appear to be extensively glycosylated."
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Determined pH optimum (6.8) and temperature optimum (75 degrees C)
"The pH and temperature optima of the enzyme were 6.8 and 75 degrees C respectively"