title: Phosphate concentration regulates transcription of the Acinetobacter polyhydroxyalkanoic acid biosynthetic genes.
abstract: The polyhydroxyalkanoic acid (PHA) biosynthetic gene locus was cloned and characterized from an Acinetobacter sp. isolated from activated sludge. Nucleotide sequence analysis identified three clustered genes, phaAAc (encoding a beta-ketothiolase), phaBAc (encoding an acetoacetyl coenzyme A reductase), and phaCAc (encoding a PHA synthase). In addition, an open reading frame (ORF1) with potential to encode a 13-kDa protein was identified within this locus. The sequence of the putative translational product of ORF1 does not show significant similarity to any sequences in the database. A plasmid containing the Acinetobacter pha locus conferred the ability to accumulate poly-beta-hydroxybutyrate on its Escherichia coli host. These genes appear to lie in an operon transcribed by two promoters upstream of phaBAc, an apparent constitutive promoter, and a second promoter induced by phosphate starvation and under pho regulon control. These as well as a number of additional potential transcription start points were identified by a combination of primer extension and promoter-chloramphenicol acetyltransferase gene fusion studies carried out in Acinetobacter or E. coli transformants.
authors.affiliation: Department of Microbiology, Monash University, Clayton, Victoria, Australia.
authors.forename: M A
authors.initials: MA
authors.lastname: Schembri
authors.forename: R C
authors.initials: RC
authors.lastname: Bayly
authors.forename: J K
authors.initials: JK
authors.lastname: Davies
mesh_terms: D000102:Acetyl-CoA C-Acyltransferase / Q000096:biosynthesis / Q000235:genetics; D000150:Acinetobacter / Q000235:genetics* / Q000378:metabolism; D000217:Acyltransferases / Q000096:biosynthesis / Q000235:genetics; D000429:Alcohol Oxidoreductases / Q000096:biosynthesis / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006880:Hydroxy Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010710:Phosphates / Q000378:metabolism*; D010957:Plasmids; D011091:Polyesters / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D006880:Hydroxy Acids; D010710:Phosphates; D011091:Polyesters; D000429:Alcohol Oxidoreductases; C023744:acetoacetyl-CoA reductase; D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase; D000102:Acetyl-CoA C-Acyltransferase; D015500:Chloramphenicol O-Acetyltransferase