Phylogenetic analysis and substrate specificity of GH2 β-mannosidases from Aspergillus species

Phylogenetic analysis of glycoside hydrolase family 2 including Aspergillus sequences and characterised beta-mannosidases from other organisms, clusters putative Aspergillus beta-mannosidases in two distinct clades (A and B). Aspergillus species have at least one paralog in each of the two clades. It appears that clade A members are extracellular and clade B members intracellular. Substrate specificity analysis of MndA of Aspergillus niger (clade A) and MndB of Aspergillus nidulans (clade B) show that MndB, in contrast to MndA, does not hydrolyse polymeric mannan and has probably evolved to hydrolyse small unbranched beta-mannosides like mannobiose. A 3D-model of MndB provides further insight. (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.