title: The identification of the acid-base catalyst of alpha-arabinofuranosidase from Geobacillus stearothermophilus T-6, a family 51 glycoside hydrolase.
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.
authors.affiliation: Department of Food Engineering and Biotechnology, Technion Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Dalia
authors.initials: D
authors.lastname: Shallom
authors.forename: Valery
authors.initials: V
authors.lastname: Belakhov
authors.forename: Dmitry
authors.initials: D
authors.lastname: Solomon
authors.forename: Sara
authors.initials: S
authors.lastname: Gilead-Gropper
authors.forename: Timor
authors.initials: T
authors.lastname: Baasov
authors.forename: Gil
authors.initials: G
authors.lastname: Shoham
authors.forename: Yuval
authors.initials: Y
authors.lastname: Shoham
mesh_terms: D000143:Acids / Q000737:chemistry; D000468:Alkalies / Q000737:chemistry; D001386:Azides / Q000737:chemistry; D001407:Bacillus; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D001665:Binding Sites / Q000502:physiology; D020134:Catalytic Domain / Q000502:physiology*; D003001:Cloning, Molecular; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D016297:Mutagenesis, Site-Directed; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D017550:Spectroscopy, Fourier Transform Infrared; D014994:Xylose / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D000143:Acids; D000468:Alkalies; D001386:Azides; D001426:Bacterial Proteins; C431715:xylopyranose; D014994:Xylose; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase