title: A novel protein that binds to dnrN-dnrO intergenic region of Streptomyces peucetius purified by DNA affinity capture has dihydrolipoamide dehydrogenase activity.
abstract: An antitumour chemotherapeutic, daunorubicin (DNR), produced by Streptomyces peucetius exhibits cytotoxic activity through topoisomerase-mediated interaction with DNA, thereby inhibiting DNA replication and repair and RNA and protein synthesis. It is synthesized by the type II polyketide pathway. Understanding molecular mechanisms that drive expression of antibiotic biosynthetic genes in response to diverse signals and chemical inducers is of considerable interest. Intergenic DNA between regulatory genes dnrN and dnrO of DNR biosynthesis pathway in S. peucetius has a promoter for transcription of dnrN in one strand and three promoters in the opposite strand for dnrO. Studies have shown that DnrO binds to a specific sequence in this region to activate transcription of dnrN. In the present study, using biotinylated intergenic DNA in combination with streptavidin magnetic beads, we have purified a protein that binds to this target sequence. The protein has been characterized by nano LC ESI MS/MS mass spectrometry. Sequence similarity searches for effective identification of protein by genome databases comparisons led to identification of a sequence-specific DNA binding protein that exhibits dihydrolipoamide dehydrogenase (DLDH) activity suggesting that this protein may be involved in regulation of DNR biosynthesis.
authors.affiliation: Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai 625 021, India. ajithvasanthan@gmail.com
authors.forename: Vasantha Kumar
authors.initials: VK
authors.lastname: Ajith
authors.forename: Ranjan
authors.initials: R
authors.lastname: Prasad
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002846:Chromatography, Affinity / Q000379:methods*; D021901:DNA, Intergenic / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D003630:Daunorubicin / Q000096:biosynthesis; D008058:Dihydrolipoamide Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D008863:Microspheres; D009243:NAD / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D013302:Streptomyces / Q000378:metabolism*; D053719:Tandem Mass Spectrometry; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D021901:DNA, Intergenic; D004268:DNA-Binding Proteins; C092188:DnrN protein, Streptomyces peucetius; D011994:Recombinant Proteins; D014157:Transcription Factors; D009243:NAD; D008058:Dihydrolipoamide Dehydrogenase; D003630:Daunorubicin