Molecular characterization of a glycoside hydrolase family-51 α-L-arabinofuranosidase from Auricularia auricula

The cDNA encoding α-L-arabinofuranosidase was cloned from the edible fungus Auricularia auricula for the first time. The open reading frame of the α-L-arabinofuranosidase gene abf was 1953 bp encoding 650 amino acids, with a predicted protein molecular weight of 71.19 kDa and a theoretical isoelectric point of 5.23. The putative protein was predicted to belong to the glycoside hydrolase family-51. In addition, abf was cloned into the pET-32a vector and then expressed in Escherichia coli BL21. The recombinant protein, with an expected molecular weight, was observed in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Moreover, the transcription levels of abf in response to different carbon sources were investigated in this study. The results showed that the expression of abf was mostly up-regulated when the mycelia were grown in different carbon sources, and L-arabinose or maltose induction had a significant effect on the expression of abf, which was 5.13- and 4.58-fold higher than that in the untreated control sample, respectively. In addition, the highest transcript levels induced by glucose and sucrose appeared on the third day and the levels were 2.47- and 3.11-fold higher compared to the control. These results laid a foundation for further studies on the α-L-arabinofuranosidase from A. auricula