5UBJ

Structure of an alpha-L-arabinofuranosidase (GH62) from Aspergillus nidulans

Summary for 5UBJ

• Entry DOI: 10.2210/pdb5ubj/pdb
• Descriptor: Alpha-L-arabinofuranosidase axhA-2, CALCIUM ION (3 entities in total)
• Functional Keywords: arabinofuranosidase, hemicellulose, hydrolase
• Biological source: Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139)
• Total number of polymer chains: 1
• Total formula weight: 36060.82

Authors

Liberato, M.V.,Contesini, F.J.,Damasio, A.R.,Squina, F.M. (deposition date: 2016-12-20, release date: 2017-09-27, Last modification date: 2024-11-13)

Primary citation

Contesini, F.J.,Liberato, M.V.,Rubio, M.V.,Calzado, F.,Zubieta, M.P.,Riano-Pachon, D.M.,Squina, F.M.,Bracht, F.,Skaf, M.S.,Damasio, A.R.
Structural and functional characterization of a highly secreted alpha-l-arabinofuranosidase (GH62) from Aspergillus nidulans grown on sugarcane bagasse.
Biochim. Biophys. Acta, 1865:1758-1769, 2017

PubMed Abstract: Carbohydrate-Active Enzymes are key enzymes for biomass-to-bioproducts conversion. α-l-Arabinofuranosidases that belong to the Glycoside Hydrolase family 62 (GH62) have important applications in biofuel production from plant biomass by hydrolyzing arabinoxylans, found in both the primary and secondary cell walls of plants. In this work, we identified a GH62 α-l-arabinofuranosidase (AnAbf62A) that was highly secreted when Aspergillus nidulans was cultivated on sugarcane bagasse. The gene AN7908 was cloned and transformed in A. nidulans for homologous production of AnAbf62A, and we confirmed that the enzyme is N-glycosylated at asparagine 83 by mass spectrometry analysis. The enzyme was also expressed in Escherichia coli and the studies of circular dichroism showed that the melting temperature and structural profile of AnAbf62A and the non-glycosylated enzyme from E. coli (AnAbf62A) were highly similar. In addition, the designed glycomutant AnAbf62A presented similar patterns of secretion and activity to the AnAbf62A, indicating that the N-glycan does not influence the properties of this enzyme. The crystallographic structure of AnAbf62A was obtained and the 1.7Å resolution model showed a five-bladed β-propeller fold, which is conserved in family GH62. Mutants AnAbf62A and AnAbf62A showed that Y312 was an important substrate-binding residue. Molecular dynamics simulations indicated that the loop containing Y312 could access different conformations separated by moderately low energy barriers. One of these conformations, comprising a local minimum, is responsible for placing Y312 in the vicinity of the arabinose glycosidic bond, and thus, may be important for catalytic efficiency.

PubMed: 28890404
DOI: 10.1016/j.bbapap.2017.09.001

Experimental method

X-RAY DIFFRACTION (1.7 Å)