Biomaterial Database

Conformation of intercalated DNA plasmids investigated by circular dichroism and dynamic light scattering. 1990

G Chirico, and L Lunelli, and G Baldini

Dipartimento di Fisica, Universitá di Milano, Italy.

Two DNA plasmids, pEGF and pACL29, intercalated with ethidium bromide (EB), have been examined by circular dichroism (CD) and dynamic light scattering (DLS). CD and DLS data show significant changes when the EB/DNA (phosphates) ratio reaches a value of r approximately equal to 0.13. The translational and rotational diffusion coefficients, predicted assuming that plasmids can be described by a string of beads, and the CD spectrum, suggest that a transition from an interwound to a toroidal conformation is likely to occur.

UI	MeSH Term	Description	Entries
D008027	Light	That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.	Light, Visible,Photoradiation,Radiation, Visible,Visible Radiation,Photoradiations,Radiations, Visible,Visible Light,Visible Radiations
D008962	Models, Theoretical	Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Experimental Model,Experimental Models,Mathematical Model,Model, Experimental,Models (Theoretical),Models, Experimental,Models, Theoretic,Theoretical Study,Mathematical Models,Model (Theoretical),Model, Mathematical,Model, Theoretical,Models, Mathematical,Studies, Theoretical,Study, Theoretical,Theoretical Model,Theoretical Models,Theoretical Studies
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
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004278	DNA, Superhelical	Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.	DNA, Supercoiled,DNA, Supertwisted,Supercoiled DNA,Superhelical DNA,Supertwisted DNA
D004996	Ethidium	A trypanocidal agent and possible antiviral agent that is widely used in experimental cell biology and biochemistry. Ethidium has several experimentally useful properties including binding to nucleic acids, noncompetitive inhibition of nicotinic acetylcholine receptors, and fluorescence among others. It is most commonly used as the bromide.	Ethidium Bromide,Homidium Bromide,Novidium,Bromide, Ethidium,Bromide, Homidium
D012542	Scattering, Radiation	The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Radiation Scattering,Radiation Scatterings,Scatterings, Radiation