Abstract
The alpha-L-arabinofuranosidase from Geobacillus stearothermophilus T-6 (AbfA T-6) belongs to the retaining family 51 glycoside hydrolases. The conserved Glu175 was proposed to be the acid-base catalytic residue. AbfA T-6 exhibits residual activity towards aryl beta-D-xylopyranosides. This phenomenon was used to examine the catalytic properties of the putative acid-base mutant E175A. Data from kinetic experiments, pH profiles, azide rescue, and the identification of the xylopyranosyl azide product provide firm support to the assignment of Glu175 as the acid-base catalyst of AbfA T-6.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Acids / chemistry
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Alkalies / chemistry
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Azides / chemistry
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Bacillus
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Bacterial Proteins / chemistry
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Bacterial Proteins / genetics
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Binding Sites / physiology
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Catalytic Domain / physiology*
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Cloning, Molecular
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Glycoside Hydrolases / chemistry*
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Glycoside Hydrolases / genetics
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Kinetics
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Magnetic Resonance Spectroscopy
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Mass Spectrometry
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Mutagenesis, Site-Directed
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Sequence Analysis, DNA
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Sequence Homology, Amino Acid
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Spectroscopy, Fourier Transform Infrared
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Xylose / analogs & derivatives*
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Xylose / chemistry
Substances
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Acids
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Alkalies
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Azides
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Bacterial Proteins
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xylopyranose
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Xylose
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Glycoside Hydrolases
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alpha-N-arabinofuranosidase