FIGURE 9.

The chitooligosaccharide utilization pathway in E. coli. The scheme is based on the GlcNAc-utilization pathway proposed by Yang et al. (14) and Verma and Mahadevan (15). Solid arrows denote enzymic reactions, and dotted arrows denote the direction of sugar transport. PTS, phosphoenolpyruvate transferase system; OM, outer membrane; IM, inner membrane; ?Hex, uncharacterized β-N-acetylglucosaminidase (EC 3.2.1.96); ChbG, chitooligosaccharide monodeacetylase (EC 3.5.1.105); ChbF, monoacetyl-chitobiose 6-phosphate hydrolase (EC 3.2.1.86); NagA, N-acetylglucosamine-6-phosphate deacetylase (EC 3.5.1.25); NagB, glucosamine-6-phosphate deaminase (EC 3.5.1.10).