If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Locations of Mapped Genes:
|Superclasses:||Degradation/Utilization/Assimilation → Carbohydrates Degradation → Sugars Degradation|
The β-glucoside N,N'-diacetylchitobiose is the major breakdown product of chitin, the second most abundant biopolymer after cellulose. E. coli is capable of using N,N'-diacetylchitobiose as the sole source of carbon [Keyhani97].
Chitobiose is imported and concurrently phosphorylated to N,N'-diacetylchitobiose 6'-phosphate by the chitobiose PTS transporter. Recent evidence suggests that this is followed by deacetylation of the unphosphorylated acetylglucosamine moiety at the reducing end of N,N'-diacetylchitobiose 6'-phosphate by chito-oligosaccharide mono-deacetylase [Verma12]. N-monoacetylchitobiose 6'-phosphate is subsequently hydrolyzed by the glycosyl hydrolase monoacetylchitobiose-6-phosphate hydrolase to D-glucosamine and N-acetyl-D-glucosamine 6-phosphate. N-acetyl-D-glucosamine 6-phosphate enters the N-acetylglucosamine degradation I pathway for conversion to β-D-fructofuranose 6-phosphate, which enters glycolysis. The fate of D-glucosamine is currently unclear; when used as a carbon source, D-glucosamine enters the cell via a PTS transporter and is thereby phosphorylated. It is possible that an intracellular D-glucosamine kinase activity enables utilization of this compound.
Please note that biochemical assays of both chito-oligosaccharide mono-deacetylase and monoacetylchitobiose-6-phosphate hydrolase have involved substrates that are related, but not identical to the compounds in this pathway.
Keyhani97: Keyhani NO, Roseman S (1997). "Wild-type Escherichia coli grows on the chitin disaccharide, N,N'-diacetylchitobiose, by expressing the cel operon." Proc Natl Acad Sci U S A 1997;94(26);14367-71. PMID: 9405618
Tilly01: Tilly K, Elias AF, Errett J, Fischer E, Iyer R, Schwartz I, Bono JL, Rosa P (2001). "Genetics and regulation of chitobiose utilization in Borrelia burgdorferi." J Bacteriol 183(19);5544-53. PMID: 11544216
Brombacher03: Brombacher E, Dorel C, Zehnder AJ, Landini P (2003). "The curli biosynthesis regulator CsgD co-ordinates the expression of both positive and negative determinants for biofilm formation in Escherichia coli." Microbiology 149(Pt 10);2847-57. PMID: 14523117
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Khersonsky11: Khersonsky O, Malitsky S, Rogachev I, Tawfik DS (2011). "Role of chemistry versus substrate binding in recruiting promiscuous enzyme functions." Biochemistry 50(13);2683-90. PMID: 21332126
Plumbridge04: Plumbridge J, Pellegrini O (2004). "Expression of the chitobiose operon of Escherichia coli is regulated by three transcription factors: NagC, ChbR and CAP." Mol Microbiol 52(2);437-49. PMID: 15066032
Thompson99: Thompson J, Ruvinov SB, Freedberg DI, Hall BG (1999). "Cellobiose-6-phosphate hydrolase (CelF) of Escherichia coli: characterization and assignment to the unusual family 4 of glycosylhydrolases." J Bacteriol 181(23);7339-45. PMID: 10572139
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