Biomaterial Database

Secondary structure specificity of the nuclease activity of the 1,10-phenanthroline-copper complex. 1984

L E Pope, and D S Sigman

The artificial DNase activity of the 1,10-phenanthroline-cuprous ion complex [(OP)2Cu+] and H2O2 cleaves the A, B, and Z forms of DNA at different rates. The B structure, formed by most DNAs including poly(dA-dT) and poly(dA) X poly(dT), is the most susceptible to cleavage. It is completely degraded within 1 min by 40 microM 1,10-phenanthroline/4 microM Cu2+/7 mM H2O2/7 mM 3-mercaptopropionic acid. The A structure, formed by RNA X DNA hybrids such as poly(rA) X poly(dT), is cleaved in both strands roughly 10-20% as rapidly as poly(dA-dT) under comparable conditions. In contrast, the left-handed Z structure, formed by poly(dG-dC) in 3.0 M NaCl, is completely resistant to cleavage even though the same copolymer in the B structure at 15 mM NaCl is readily degraded. Poly(dA-dT) is rendered acid soluble at both salt concentrations at similar rates. The basis for the secondary structure specificity of the DNA cleavage reaction most likely resides in the requisite formation of a productive complex between (OP)2Cu+ and DNA during the course of this reaction. Previous studies have suggested that strand scission is due to oxidative destruction of the deoxyribose by hydroxyl radicals produced by the oxidation of DNA-bound Cu+ by H2O2. Apparently, the Z and A structures are unable to form a stable noncovalent complex with the same optimal geometry for cleavage as the B structure and are less susceptible to degradation. This artificial DNase activity may provide an approach to assess the formation of non-B-DNA structures in solution.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D010618	Phenanthrolines		Phenanthroline
D011119	Polynucleotides	BIOPOLYMERS composed of NUCLEOTIDES covalently bonded in a chain. The most common examples are DNA and RNA chains.	Polynucleotide
D003851	Deoxyribonucleases	Enzymes which catalyze the hydrolases of ester bonds within DNA. EC 3.1.-.	DNAase,DNase,Deoxyribonuclease,Desoxyribonuclease,Desoxyribonucleases,Nucleases, DNA,Acid DNase,Alkaline DNase,DNA Nucleases,DNase, Acid,DNase, Alkaline
D004256	DNA Polymerase I	A DNA-dependent DNA polymerase characterized in prokaryotes and may be present in higher organisms. It has both 3'-5' and 5'-3' exonuclease activity, but cannot use native double-stranded DNA as template-primer. It is not inhibited by sulfhydryl reagents and is active in both DNA synthesis and repair.	DNA Polymerase alpha,DNA-Dependent DNA Polymerase I,Klenow Fragment,DNA Pol I,DNA Dependent DNA Polymerase I,Polymerase alpha, DNA
D004720	Endonucleases	Enzymes that catalyze the hydrolysis of the internal bonds and thereby the formation of polynucleotides or oligonucleotides from ribo- or deoxyribonucleotide chains. EC 3.1.-.	Endonuclease
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
D001236	Aspergillus oryzae	An imperfect fungus present on most agricultural seeds and often responsible for the spoilage of seeds in bulk storage. It is also used in the production of fermented food or drink, especially in Japan.	Eurotium oryzae
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