화학공학소재연구정보센터
Biotechnology and Bioengineering, Vol.115, No.1, 41-49, 2018
Constructing arabinofuranosidases for dual arabinoxylan debranching activity
Enzymatic conversion of arabinoxylan requires -L-arabinofuranosidases able to remove -L-arabinofuranosyl residues (-L-Araf) from both mono- and double-substituted D-xylopyranosyl residues (Xylp) in xylan (i.e., AXH-m and AXH-d activity). Herein, SthAbf62A (a family GH62 -L-arabinofuranosidase with AXH-m activity) and BadAbf43A (a family GH43 -L-arabinofuranosidase with AXH-d3 activity), were fused to create SthAbf62A_BadAbf43A and BadAbf43A_SthAbf62A. Both fusion enzymes displayed dual AXH-m,d and synergistic activity toward native, highly branched wheat arabinoxylan (WAX). When using a customized arabinoxylan substrate comprising mainly -(13)-L-Araf and -(12)-L-Araf substituents attached to disubstituted Xylp (d-2,3-WAX), the specific activity of the fusion enzymes was twice that of enzymes added as separate proteins. Moreover, the SthAbf62A_BadAbf43A fusion removed 83% of all -L-Araf from WAX after a 20hr treatment. H-1 NMR analyses further revealed differences in SthAbf62A_BadAbf43 rate of removal of specific -L-Araf substituents from WAX, where 9.4 times higher activity was observed toward d--(13)-L-Araf compared to m--(13)-L-Araf positions.