D-arabinose metabolism in Escherichia coli B: induction and cotransductional mapping of the L-fucose-D-arabinose pathway enzymes.
D-Arabinose is degraded by Escherichia coli B via some of the L-fucose pathway enzymes and a D-ribulokinase which is distinct from the L-fuculokinase of the L-fucose pathway. We found that L-fucose and D-arabinose acted as the apparent inducers of the enzymes needed for their degradation. These enzymes, including D-ribulokinase, appeared to be coordinately regulated, and mutants which constitutively synthesized the L-fucose enzymes also constitutively synthesized D-ribulokinase. In contrast to D-arabinose-positive mutants of E. coli K-12, in which L-fuculose-1-phosphate and D-ribulose-1-phosphate act as inducers of the L-fucose pathway, we found that these intermediates did not act as inducers in E. coli B. To further characterize the E. coli B system, some of the L-fucose-D-arabinose genes were mapped by using bacteriophage P1 transduction. A transposon Tn10 insertion near the E. coli B L-fucose regulon was used in two- and three-factor reciprocal crosses. The gene encoding D-ribulokinase, designated darK, was found to map within the L-fucose regulon, and the partial gene order was found to be Tn10-fucA-darK-fucI-fucK-thyA.
Elsinghorst
E A
EA
Department of Microbiology, Cornell University, Ithaca, New York 14853.
Mortlock
R P
RP
D001089:Arabinose / Q000378:metabolism*; D004798:Enzymes / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005643:Fucose / Q000378:metabolism*; D005796:Genes; D005798:Genes, Bacterial; D005838:Genotype; D009154:Mutation; D010641:Phenotype; D014161:Transduction, Genetic
D004798:Enzymes; D005643:Fucose; D001089:Arabinose