title: Proteins encoded by the conservon of Streptomyces coelicolor A3(2) comprise a membrane-associated heterocomplex that resembles eukaryotic G protein-coupled regulatory system.
abstract: Streptomyces coelicolor A3(2) retains unique conserved operons termed conservons. Here, one of the conservons (cvn9), which encodes five proteins (A9-E9), was characterized. Mutants for cvnA9 and cvnAlO conditionally overproduced actinorhodin and performed precocious aerial growth, while a cvnE9 mutant showed the parental phenotype. Transcription of bidG, adpA and bldN was upregulated in the cvnA9 mutant. A9-D9 were detected in the insoluble fraction of cell-free extract of S. coelicolor by Western analysis. Biochemical analyses revealed that A9 has ATP-hydrolysing and adenine nucleotide-binding activities; D9 has GTP-hydrolysing and guanine nucleotide-binding activities; and E9 shows a typical spectrum similar to cytochrome P450. The comprehensive interaction assays demonstrated the occurrence of specific interactions between A9 and B9, A9 and C9, B9 and B9, B9 and D9, and C9 and D9. A9 associated with and dissociated from B9 (and C9) when ATP and ATP-gamma-S were supplied in the reaction respectively. Similarly, D9 associated with and dissociated from B9 (and C9) when GTP and GTP-gamma-S were supplied respectively. A9 and B9 were also shown for the occurrence as homocomplexes. Probably, Cvn9 proteins comprise a membrane-associated heterocomplex resembling the eukaryotic G-protein-coupled receptor system, which may serve as a signal transducer that connects to the bld cascade.
authors.affiliation: Life Science Research Center, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa 252-8510, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Komatsu
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takano
authors.forename: Tomonari
authors.initials: T
authors.lastname: Hiratsuka
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishigaki
authors.forename: Kyoko
authors.initials: K
authors.lastname: Shimada
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Beppu
authors.forename: Kenji
authors.initials: K
authors.lastname: Ueda
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009876:Operon; D010641:Phenotype; D011485:Protein Binding; D048372:Streptomyces coelicolor / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; D046912:Multiprotein Complexes; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D019204:GTP-Binding Proteins