A response-regulator-like activator of antibiotic synthesis from Streptomyces coelicolor A3(2) with an amino-terminal domain that lacks a phosphorylation pocket.
In Streptomyces coelicolor A3(2), bldA mutants that lack the tRNA for the rare leucine codon UUA fail to make the red undecylprodigiosin antibiotic complex. To find out why, red-pigmented while bald (Pwb) derivatives of a bldA mutant were isolated. Using a cloning strategy that allowed for (and demonstrated) dominance of the mutations, they were localized to the red gene cluster. By using insert-mediated integration of a phi C31 phage-based vector, one of the Pwb mutations was more precisely located between red structural genes to a segment of approximately 1 kb about 4 kb from the known pathway-specific regulatory gene redD. The segment contained most of an ORF (redZ) encoding a protein (RedZ) with end-to-end similarity to response regulators of diverse function from a variety of bacteria. Remarkably, in RedZ hydrophobic residues replace nearly all of the charged residues that usually make up the phosphorylation pocket present in typical response regulators, including the aspartic acid residue that is normally phosphorylated by a cognate sensory protein kinase. A single TTA codon in redZ provided a potential explanation for the bldA-dependence of undecylprodigiosin synthesis. This codon was unchanged in three Pwb mutants, but further analysis of one of the mutants revealed a potential up-promoter mutation. It seems possible that a combination of low-level natural translation of the UUA codon by a charged non-cognate tRNA, coupled with increased transcription of redZ in the Pwb mutant allows the accumulation of a threshold level of the RedD protein.
Guthrie
Ellen P
EP
John Innes Centre, Norwich Research Park,Colney, Norwich NR4 7UH,UK.
Flaxman
Christine S
CS
Department of Biological Sciences, University of Warwick,Coventry CV4 7AL,UK.
White
Janet
J
John Innes Centre, Norwich Research Park,Colney, Norwich NR4 7UH,UK.
Hodgson
David A
DA
Department of Biological Sciences, University of Warwick,Coventry CV4 7AL,UK.
Bibb
Mervyn J
MJ
John Innes Centre, Norwich Research Park,Colney, Norwich NR4 7UH,UK.
Chater
Keith F
KF
John Innes Centre, Norwich Research Park,Colney, Norwich NR4 7UH,UK.
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins; D001483:Base Sequence; D003062:Codon; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005822:Genetic Vectors; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010766:Phosphorylation; D010802:Phylogeny; D011353:Prodigiosin / Q000031:analogs & derivatives / Q000096:biosynthesis; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial; D012356:RNA, Transfer, Leu / Q000235:genetics; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C107344:BldA tRNA, Streptomyces coelicolor; D003062:Codon; D012329:RNA, Bacterial; D012356:RNA, Transfer, Leu; C104042:RedZ protein, Streptomyces coelicolor; D015534:Trans-Activators; C077706:redD protein, Streptomyces coelicolor; C047347:undecylprodigiosin; D011353:Prodigiosin