Biomaterial Database

Inhibition of transcription of supercoiled PM2 DNA by carbodiimide modification. 1977

M S Flashner, and M A Katopes, and J Lebowitz

PM2 superhelican DNA (form I), which as been reacted with the single strand specific reagent, N-cyclohexyl-N'-beta-(methylmorpholinium)ethyl carbodiimide (CMC) is more than 95% inhibited in its ability to support transcription with E. coli B RNA polymerase in vitro. Almost complete inhibition of transcription was achieved after 2 hours of reaction with FI when only 1% of the bases were modified. A large increase in S20,* (from 26.8 S to 33.6 S) of FI DNA was observed during the course of reaction. Rifampicin resistant transcription is more susceptible to inhibition by CMC than total transcription, suggesting that the CMC is preferentially binding at promoter sites. These results clearly are in accord with the observation that supercoiled DNA contains localized regions of unpaired bases. The promotor sites for E. coli RNA polymerase in FI PM2 DNA appear to be located at or near these unpaired sites.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009025	Morpholines		Tetrahydro-1,4-Oxazines,Tetrahydro 1,4 Oxazines
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D002234	Carbodiimides	Compounds with the general formula RN	Carbodiimide
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D012293	Rifampin	A semisynthetic antibiotic produced from Streptomyces mediterranei. It has a broad antibacterial spectrum, including activity against several forms of Mycobacterium. In susceptible organisms it inhibits DNA-dependent RNA polymerase activity by forming a stable complex with the enzyme. It thus suppresses the initiation of RNA synthesis. Rifampin is bactericidal, and acts on both intracellular and extracellular organisms. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1160)	Rifampicin,Benemycin,Rifadin,Rimactan,Rimactane,Tubocin
D012321	DNA-Directed RNA Polymerases	Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).	DNA-Dependent RNA Polymerases,RNA Polymerases,Transcriptases,DNA-Directed RNA Polymerase,RNA Polymerase,Transcriptase,DNA Dependent RNA Polymerases,DNA Directed RNA Polymerase,DNA Directed RNA Polymerases,Polymerase, DNA-Directed RNA,Polymerase, RNA,Polymerases, DNA-Dependent RNA,Polymerases, DNA-Directed RNA,Polymerases, RNA,RNA Polymerase, DNA-Directed,RNA Polymerases, DNA-Dependent,RNA Polymerases, DNA-Directed
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription