RNA polymerase in vegetative cells of Bacillus subtilis. I. Purification and properties of RNA polymerase L1 and L2.
Two forms of RNA polymerase [EC 2.7.7.6], RPase L1 and RPase L2, isolated from a highly synchronized vegetative culture of Bacillus subtilis Marburg strain are described. RPase L1 is the major component (identical and the vegetative RNA polymerase already reported) and RPase L2 is a minor, new component corresponding to 3--5% of the total activity. The enzymes differed in their requirements for divalent ions, though the differences depended on the template DNA employed. PRase L1 is able to transcribe phage M2 DNA in the presence of Mg2+ ions and both B. subtilis DNA and phage M2 DNA in the presence of Mn2+ ions. On the other hand, RPase L2 activity can be detected only in the presence of 3 mM Mn2+ ions with all the templates. It is of interest that the transcription of phage M2 DNA by both enzymes stringently requires KC1. It may be due to this ion dependence that RPase L2 has not been detected previously. RPase L2 consists of 1beta', 1beta gamma, 1sigma, and 2alpha subunits. The molecular weight of the beta gamma subunit (about 110,000) is close to the value reported for the beta subunit of RNA polymerase prepared from sporulating cells. However, RPase L2 as a whole molecule is different from the RNA polymerase of sporulating cells or spores in the following two respects: RPase L2 contains sigma subunit as a component essential for selective transcription, and it is resistant to 1 mug of rifampicin per ml. Elimination of the sigma subunit from RPase L2 greatly stimulates RNA synthesis by the enzyme. Conversely, the addition of sigma subunit to the core-enzyme is inhibitory.
D001412:Bacillus subtilis / Q000201:enzymology*; D002455:Cell Division; D012321:DNA-Directed RNA Polymerases / Q000302:isolation & purification; D004789:Enzyme Activation; D007700:Kinetics; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D009994:Osmolar Concentration; D011189:Potassium Chloride / Q000494:pharmacology; D012318:RNA Polymerase I / Q000302:isolation & purification / Q000378:metabolism; D012319:RNA Polymerase II / Q000302:isolation & purification / Q000378:metabolism; D013698:Templates, Genetic; D013997:Time Factors
D046911:Macromolecular Substances; D008345:Manganese; D011189:Potassium Chloride; D012319:RNA Polymerase II; D012321:DNA-Directed RNA Polymerases; D012318:RNA Polymerase I; D008274:Magnesium