Mannan-degrading enzymes from Cellulomonas fimi

The genes man26a and man2A from Cellulomonas fimi encode mannanase 26A (Man 26A) and beta-mannosidase 2A (Man2A), respectively. Mature Man26A is a secr eted, modular protein of 951 amino acids, comprising a catalytic module in family 26 of glycosyl hydrolases, an S-layer homology module, and two modul es of unknown function. Exposure of Man26A produced by Escherichia coli to C. fimi protease generates active fragments of the enzyme that correspond t o polypeptides with mannanase activity produced by C. fimi during growth on mannans, indicating that it may be the only mannanase produced by the orga nism. A significant fraction of the Man26A produced by C. fimi remains cell associated. Man2A is an intracellular enzyme comprising a catalytic module in a subfamily of family 2 of the glycosyl hydrolases that at present cont ains only mammalian beta-mannosidases.