alba romero - Academia.edu (original) (raw)
Uploads
Papers by alba romero
Critical reviews in …, 2010
Microbial secondary metabolites are low molecular mass products, not essential for growth of the ... more Microbial secondary metabolites are low molecular mass products, not essential for growth of the producing cultures, but very important for human health. They include antibiotics, antitumor agents, cholesterol-lowering drugs, and others. They have unusual structures and are ...
Critical Reviews in Microbiology, 2010
Journal of Antibiotics, 2010
The SCO7222 protein and ActR are two of ϳ150 TetR-like transcription factors encoded in the Strep... more The SCO7222 protein and ActR are two of ϳ150 TetR-like transcription factors encoded in the Streptomyces coelicolor genome. Using bioluminescence as a readout, we have developed Escherichia coli-based biosensors that accurately report the regulatory activity of these proteins and used it to investigate their interactions with DNA and small-molecule ligands. We found that the SCO7222 protein and ActR repress the expression of their putative target genes, SCO7223 and actII-ORF2 (actA), respectively, by interacting with operator sequence in the promoters. The operators recognized by the two proteins are related such that O 7223 (an operator for SCO7223) could be bound by both the SCO7222 protein and ActR with similar affinities. In contrast, O act (an operator for actII-ORF2) was bound tightly by ActR and more weakly by the SCO7222 protein. We demonstrated ligand specificity of these proteins by showing that while TetR (but not ActR or the SCO7222 protein) interacts with tetracyclines, ActR (but not TetR or the SCO7222 protein) interacts with actinorhodin and related molecules. Through operator-targeted mutagenesis, we found that at least two nucleotide changes in O 7223 were required to disrupt its interaction with SCO7222 protein, while ActR was more sensitive to changes on O act . Most importantly, we found that the interaction of each protein with wild-type and mutant operator sequences in vivo and in vitro correlated perfectly. Our data suggest that E. coli-based biosensors of this type should be broadly applicable to TetR-like transcription factors.
Critical reviews in …, 2010
Microbial secondary metabolites are low molecular mass products, not essential for growth of the ... more Microbial secondary metabolites are low molecular mass products, not essential for growth of the producing cultures, but very important for human health. They include antibiotics, antitumor agents, cholesterol-lowering drugs, and others. They have unusual structures and are ...
Critical Reviews in Microbiology, 2010
Journal of Antibiotics, 2010
The SCO7222 protein and ActR are two of ϳ150 TetR-like transcription factors encoded in the Strep... more The SCO7222 protein and ActR are two of ϳ150 TetR-like transcription factors encoded in the Streptomyces coelicolor genome. Using bioluminescence as a readout, we have developed Escherichia coli-based biosensors that accurately report the regulatory activity of these proteins and used it to investigate their interactions with DNA and small-molecule ligands. We found that the SCO7222 protein and ActR repress the expression of their putative target genes, SCO7223 and actII-ORF2 (actA), respectively, by interacting with operator sequence in the promoters. The operators recognized by the two proteins are related such that O 7223 (an operator for SCO7223) could be bound by both the SCO7222 protein and ActR with similar affinities. In contrast, O act (an operator for actII-ORF2) was bound tightly by ActR and more weakly by the SCO7222 protein. We demonstrated ligand specificity of these proteins by showing that while TetR (but not ActR or the SCO7222 protein) interacts with tetracyclines, ActR (but not TetR or the SCO7222 protein) interacts with actinorhodin and related molecules. Through operator-targeted mutagenesis, we found that at least two nucleotide changes in O 7223 were required to disrupt its interaction with SCO7222 protein, while ActR was more sensitive to changes on O act . Most importantly, we found that the interaction of each protein with wild-type and mutant operator sequences in vivo and in vitro correlated perfectly. Our data suggest that E. coli-based biosensors of this type should be broadly applicable to TetR-like transcription factors.