title: A gene from Alcaligenes denitrificans that confers albicidin resistance by reversible antibiotic binding.
abstract: Albicidin antibiotics specifically block prokaryote DNA replication. The albicidin resistance gene (albB) cloned from a soil isolate of Alcaligenes denitrificans encodes a 23 kDa protein capable of detoxifying albicidin by reversible binding. This mechanism operates intracellularly to protect DNA replication in albicidin-sensitive Escherichia coli expressing the cloned resistance gene, which can be induced fivefold in the presence of 1.5 micrograms albicidin ml-1 in the surrounding medium. The coding region of 621 bp has regions with partial DNA sequence homology to an albicidin resistance gene (albA) from Klebsiella oxytoca, but with rearrangements and frame-shifts resulting in loss of protein homology. There is a short region of N-terminal homology between the albicidin resistance (Albr) proteins from A. denitrificans and K. oxytoca, although the two genes use different codons for shared amino acids. The N-terminal homology suggested a common functional domain; this was confirmed by deletion analysis, translational fusions and albicidin binding by a synthetic oligopeptide. Antibiotic binding provides a high level of albicidin resistance in E. coli. The gene appears to be a useful candidate for transfer to plants to protect plastid DNA replication from inhibition by albicidin phytotoxins involved in sugarcane leaf scald disease.
authors.affiliation: Department of Botany, University of Queensland, Brisbane, Australia.
authors.forename: W V
authors.initials: WV
authors.lastname: Basnayake
authors.forename: R G
authors.initials: RG
authors.lastname: Birch
mesh_terms: D000421:Alcaligenes / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D001483:Base Sequence; D003001:Cloning, Molecular; D004261:DNA Replication / Q000187:drug effects; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D007709:Klebsiella / Q000235:genetics; D008969:Molecular Sequence Data; D009930:Organic Chemicals; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014974:Xanthomonas / Q000378:metabolism / Q000472:pathogenicity
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D009930:Organic Chemicals; D010455:Peptides; C046156:albicidin