title: Aspergillus fumigatus Produces Two Arabinofuranosidases From Glycosyl Hydrolase Family 62: Comparative Properties of the Recombinant Enzymes.
abstract: The genes of two α-L-arabinofuranosidases (AbfI and II) from family GH 62 have been identified in the genome of Aspergillus fumigatus wmo. Both genes have been expressed in Pichia pastoris and the enzymes have been purified and characterized. AbfI is composed of 999 bp, does not contain introns and codes for a protein (ABFI) of 332 amino acid residues. abfII has 1246 bp, including an intron of 51 bp; the protein ABFII has 396 amino acid residues; it includes a family 1 carbohydrate-binding module (CBM) in the N-terminal region, followed by a catalytic module. The sequence of ABFI and the catalytic module of ABFII show a 79 % identity. Both enzymes are active on p-nitrophenyl α-L-arabinofuranoside (pNPAra) with KM of 94.2 and 3.9 mM for ABFI and II, respectively. Optimal temperature for ABFI is 37 °C and for ABFII 42 °C, while the pH optimum is about 4.5 to 5 for both enzymes. ABFII shows a higher thermostability. When assayed using natural substrates, both show higher activity over rye arabinoxylan as compared to wheat arabinoxylan. ABFII only is active on sugar beet pulp arabinan and both are inactive towards debranched arabinan. The higher thermostability, higher affinity for pNPAra and wider activity over natural substrates shown by ABFII may be related to the presence of a CBM. The availability of the recombinant enzymes may be useful in biotechnological applications for the production of arabinose.
authors.affiliation: Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Pérez
authors.affiliation: Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile. jeyzaguirre@unab.cl.
authors.forename: Jaime
authors.initials: J
authors.lastname: Eyzaguirre
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D001089:Arabinose / Q000737:chemistry / Q000378:metabolism*; D001232:Aspergillus fumigatus / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D007700:Kinetics; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D013379:Substrate Specificity; D013696:Temperature; D014990:Xylans / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D014990:Xylans; C085118:arabinoxylan; D001089:Arabinose; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase
keywords: Arabinofuranosidases; Aspergillus fumigatus; GH family 62; Heterologous expression; Pichia pastoris