title: Biotransformation of adenine and cytokinins by the rhizobacterium Serratia proteamaculans.
abstract: Approximately 60,000 microorganisms from Saskatchewan soil were screened for growth on the cytokinin N6-benzyladenine (BA) as C source. A single isolate, identified as Serratia proteamaculans, grew well on BA. The culture filtrates from S. proteamaculans were screened using reversed phase high performance liquid chromatography (RP-HPLC) for the presence of secondary metabolites. The analysis revealed a major metabolite and its chemical structure was deduced as 8-hydroxy-N6-benzyladenine (8-OHBA). Subsequently, the S. proteamaculans isolate was also found to metabolize N6-(2-isopentenyl)adenine and adenine through oxidation of C-8 of the purine ring. A clone of the S. proteamaculans xanthine dehydrogenase (Xdh, EC 1.1.1.204) encoding genes was isolated in Escherichia coli. This E. coli isolate metabolized BA to 8-OHBA. Similar to other bacterial Xdh, the S. proteamaculans enzyme was composed of two subunits. The derived amino acid sequences of these Xdh subunits were most similar (XdhA, 60%; XdhB, 72%) to those of Pseudomonas aeruginosa.
authors.affiliation: Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, Sask., Canada S7N 0W9. janet.taylor@nrc-cnrc.gc.ca
authors.forename: Janet L
authors.initials: JL
authors.lastname: Taylor
authors.forename: L Irina
authors.initials: LI
authors.lastname: Zaharia
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Erica
authors.initials: E
authors.lastname: Anderson
authors.forename: Suzanne R
authors.initials: SR
authors.lastname: Abrams
mesh_terms: D000225:Adenine / Q000378:metabolism*; D000595:Amino Acid Sequence; D001711:Biotransformation; D002384:Catalysis; D003583:Cytokinins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017386:Sequence Homology, Amino Acid; D012705:Serratia / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D012988:Soil Microbiology; D013379:Substrate Specificity; D014968:Xanthine Dehydrogenase / Q000235:genetics / Q000378:metabolism
chemical_list: D003583:Cytokinins; D014968:Xanthine Dehydrogenase; D000225:Adenine