Biomaterial Database

Chemical probes of DNA conformation: detection of Z-DNA at nucleotide resolution. 1985

B H Johnston, and A Rich

Chemical probes sensitive to alterations in DNA conformation, especially Z-DNA, have been identified. These permit cleavage of DNA at sites of unusual structure, the results of which can be displayed on a sequencing gel. Using supercoiled plasmids containing inserts of d(C-G)16 and d(C-A)31 X d(T-G)31, it was found that hydroxylamine and osmium tetraoxide react preferentially with cytosines and thymines, respectively, near B-DNA-Z-DNA junctions; diethylpyrocarbonate reacts more strongly with purines within Z-DNA regions; and dimethylsulfate and diethylsulfate react more strongly with guanines in Z-DNA that are out of phase with the usual pattern of purine-pyrimidine alternation. Our results show that B-Z boundaries are mobile and that with increasing torsional strain, the Z-DNA regions can expand to include nonalternating nucleotide sequences.

UI	MeSH Term	Description	Entries
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
D009993	Osmium Tetroxide	(T-4)-Osmium oxide (OsO4). A highly toxic and volatile oxide of osmium used in industry as an oxidizing agent. It is also used as a histological fixative and stain and as a synovectomy agent in arthritic joints. Its vapor can cause eye, skin, and lung damage.	Osmic Acid,Acid, Osmic,Tetroxide, Osmium
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
D011687	Purines	A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
D011743	Pyrimidines	A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.
D004047	Diethyl Pyrocarbonate	Preservative for wines, soft drinks, and fruit juices and a gentle esterifying agent.	Diethyl Dicarbonate,Diethyl Oxydiformate,Pyrocarbonic Acid Diethyl Ester,Diethylpyrocarbonate,Ethoxyformic Anhydride,Anhydride, Ethoxyformic,Dicarbonate, Diethyl,Oxydiformate, Diethyl,Pyrocarbonate, Diethyl
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
D006898	Hydroxylamines	Organic compounds that contain the (-NH2OH) radical.
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA