title: The mechanism of preferential synthesis of poly[r(purine)] in the transcription of poly[d(purine)] . poly[d(pyrimidine)] by T. thermophilus RNA polymerase.
abstract: The mechanism of preferential transcription on poly[d(purine)] . poly[d(pyrimidine)] was investigated using RNA polymerase of T. thermophilus HB8. Though the machinery for initiation is lacking, the core enzyme has the latent ability to synthesize poly[r(pyrimidine)] as well as poly[r(purine)]. The holoenzyme can synthesize poly[r(purine)] in the usual manner. Poly[r(pyrimidine)] synthesis by the holoenzyme is, however, forbidden. These results suggest that the sigma factor plays a crucial role in this preferential transcription, and that this preferential transcription may be useful as a model for the sense strand recognition. Various results led us to the hypothesis that the high affinity site for the poly[d(pyrimidine)] strands on the enzyme plays a very important role.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002942:Circular Dichroism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D015226:Dinucleoside Phosphates; D008848:Micromonosporaceae / Q000201:enzymology*; D009705:Nucleosides / Q000494:pharmacology; D009841:Oligonucleotides / Q000494:pharmacology; D011089:Polydeoxyribonucleotides / Q000378:metabolism*; D011108:Polymers; D011131:Polyribonucleotides / Q000378:metabolism*; D011687:Purines / Q000378:metabolism*; D011743:Pyrimidines / Q000378:metabolism*; D012808:Sigma Factor / Q000378:metabolism; D013698:Templates, Genetic; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D015226:Dinucleoside Phosphates; D009705:Nucleosides; D009841:Oligonucleotides; D011089:Polydeoxyribonucleotides; D011108:Polymers; D011131:Polyribonucleotides; D011687:Purines; D011743:Pyrimidines; D012808:Sigma Factor; D000255:Adenosine Triphosphate; D012321:DNA-Directed RNA Polymerases