title: The reconstitution of Anacystis nidulans DNA-dependent RNA polymerase from its isolated subunits.
abstract: The DNA-dependent RNA polymerase of the blud-green alga Anacystis nidulans was reconstituted from its isolated subunits in the absence of urea. Applying this technique the kinetics and the subunit requirements of the reconstitution process were analyzed. The results reveal differences with respect to the reconstitution of Escherichia coli polymerase. Reconstitution proceeds much more slowly in the case of the A. nidulans enzyme. Reconstitution here is absolutely dependent on the presence of the subunit sigma. On the other hand, the largest of the subunits of Mr=190000 can be fully substituted by a specific degradation product of this subunit of Mr=175000. Heterologous reconstitution between subunits of E. coli and A. nidulans polymerase does not result in active enzyme hybrids, showing a divergent evolution of the structure of this enzyme in these procaryotic organisms.
mesh_terms: D001665:Binding Sites; D000458:Cyanobacteria / Q000201:enzymology*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D011485:Protein Binding; D013045:Species Specificity; D014508:Urea
chemical_list: D046911:Macromolecular Substances; D014508:Urea; D012321:DNA-Directed RNA Polymerases