title: Characterization and complementation of a Pichia stipitis mutant unable to grow on D-xylose or L-arabinose.
abstract: Pichia stipitis CBS 6054 will grow on D-xylose, D-arabinose, and L-arabinose. D-Xylose and L-arabinose are abundant in seed hulls of maize, and their utilization is important in processing grain residues. To elucidate the degradation pathway for L-arabinose, we obtained a mutant, FPL-MY30, that was unable to grow on D-xylose and L-arabinose but that could grow on D-arabinitol. Activity assays of oxidoreductase and pentulokinase enzymes involved in D-xylose, D-arabinose, and L-arabinose pathways indicated that FPL-MY30 is deficient in D-xylitol dehydrogenase (D-XDH), D- and L-arabinitol dehydrogenases, and D-ribitol dehydrogenase. Transforming FPL-MY30 with a gene for xylitol dehydrogenase (PsXYL2), which was cloned from CBS 6054 (GenBank AF127801), restored the D-XDH activity and the capacity for FPL-MY30 to grow on L-arabinose. This suggested that FPL-MY30 is critically deficient in XYL2 and that the D-xylose and L-arabinose metabolic pathways have xylitol as a common intermediate. The capacity for FPL-MY30 to grow on D-arabinitol could proceed through D-ribulose.
authors.affiliation: Department of Bacteriology, University of Wisconsin, Madison 53706, USA.
authors.forename: N Q
authors.initials: NQ
authors.lastname: Shi
authors.forename: K
authors.initials: K
authors.lastname: Prahl
authors.forename: J
authors.initials: J
authors.lastname: Hendrick
authors.forename: J
authors.initials: J
authors.lastname: Cruz
authors.forename: P
authors.initials: P
authors.lastname: Lu
authors.forename: J Y
authors.initials: JY
authors.lastname: Cho
authors.forename: S
authors.initials: S
authors.lastname: Jones
authors.forename: T
authors.initials: T
authors.lastname: Jeffries
mesh_terms: D001089:Arabinose / Q000378:metabolism*; D050542:D-Xylulose Reductase; D005816:Genetic Complementation Test; D016296:Mutagenesis; D010843:Pichia / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D012639:Seeds; D013237:Stereoisomerism; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics / Q000378:metabolism; D014994:Xylose / Q000378:metabolism*; D003313:Zea mays
chemical_list: D014994:Xylose; D001089:Arabinose; D013401:Sugar Alcohol Dehydrogenases; C022529:ribitol 2-dehydrogenase; D050542:D-Xylulose Reductase