12 Fungal Genetics Newsletter Glycosyl Hydrolase Genes and Enzymes of Neurospora crassa

An analysis of the genome of Neurospora crassa has identified genes encoding 84 putative glycosyl hydrolases, representing 24 different families in Henrissat's classification. Functionally, they include enzymes for the degradation of all major polysaccharides (including cellulase, hemicellulase, chitinase and pectinase).There is evidence of high levels of gene amplification, despite the presence of RIP, as there are eight representatives of family 3 (beta-glucosidases and xylosidases), five of family 7 (endo- and exo-glucanases), six of family 13 (amylases and maltase), nine of family 18 (chitinase), eight of family 47 (ER alpha-mannosidases), eleven of family 61 (endoglucanases) and seven of family 76 (alpha-mannanases). In The Mycota III: Biochemistry and Molecular Biology, 2 edn. (ed. Brambl & Marzluf), p 243, I included a preliminary list ofnd the glycosyl hydrolases of Neurospora crassa identified in assembly 3 of the Neurospora genome (Radford, 2004). This listed putative NCU identities by glycosyl hydrolase family (Henrissat and Romeu 1995), and the different enzyme activities found in each family; n.b. in some families, different members may have different enzyme activities. These data have been reassessed in genome assembly 7, and only those confirmed by current annotation, Pfam glycosyl hydrolase family predictions and close Blast hits to homologs with identified enzyme activities are included in the table below. Glycosyl hydrolases are what might be termed “modular ” enzymes. They are normally under carbon catabolite regulation, and typically have one or more copies of the C-regulation motif (consensus 5'-G/CPyGGGG-3') upstream of the ORF. The table includes the number of such motifs identified for each gene. Some glycosyl hydrolases also have a substrate-binding domain