title: Ribitol catabolic pathway in Klebsiella aerogenes.
abstract: In Klebsiella aerogenes W70, there is an inducible pathway for the catabolism of ribitol consisting of at least two enzymes, ribitol dehydrogenase (RDH) and d-ribulokinase (DRK). These two enzymes are coordinately controlled and induced in response to d-ribulose, an intermediate of the pathway. Whereas wild-type K. aerogenes W70 are unable to utilize xylitol as a carbon and energy source, mutants constitutive for the ribitol pathway are able to utilize RDH to oxidize the unusual pentitol, xylitol, to d-xylulose. These mutants are able to grow on xylitol, presumably by utilization of the d-xylulose produced. Mutants constitutive for l-fucose isomerase can utilize the isomerase to convert d-arabinose to d-ribulose. In the presence of d-ribulose, RDH and DRK are induced, and such mutants are thus able to phosphorylate the d-ribulose by using the DRK of the ribitol pathway. Derivatives of an l-fucose isomerase-constitutive mutant were plated on d-arabinose, ribitol, and xylitol to select and identify mutations in the ribitol pathway. Using the transducing phage PW52, we were able to demonstrate genetic linkage of the loci involved. Three-point crosses, using constitutive mutants as donors and RDH(-), DRK(-) double mutants as recipients and selecting for DRK(+) transductants on d-arabinose, resulted in DRK(+)RDH(+)-constitutive, DRK(+)RDH(+)-inducible, and DRK(+)RDH(-)-inducible transductants but no detectable DRK(+)RDH(-) constitutive transductants, data consistent with the order rbtC-rbtD-rbtK, where rbtC is a control site and rbtD and rbtK correspond to the sites for the sites for the enzymes RDH and DRK, respectively.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D001089:Arabinose / Q000378:metabolism; D002238:Carbohydrate Epimerases / Q000378:metabolism; D002364:Caseins; D002474:Cell-Free System; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D003470:Culture Media; D004754:Enterobacter / Q000378:metabolism; D004790:Enzyme Induction; D005643:Fucose / Q000378:metabolism; D007661:Ketoses / Q000378:metabolism; D007709:Klebsiella / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D009154:Mutation; D010770:Phosphotransferases / Q000378:metabolism; D012266:Ribose; D013237:Stereoisomerism; D013402:Sugar Alcohols / Q000378:metabolism*; D014161:Transduction, Genetic; D014993:Xylitol / Q000378:metabolism
chemical_list: D002364:Caseins; D003470:Culture Media; D007661:Ketoses; D013402:Sugar Alcohols; D005643:Fucose; D012266:Ribose; D001089:Arabinose; D000429:Alcohol Oxidoreductases; D010770:Phosphotransferases; D002238:Carbohydrate Epimerases; D014993:Xylitol