Biomaterial Database

Secondary structural modifications as a consequence of in vitro acetylation and phenanthrylation of DNA by the ultimate carcinogen N-acetoxy-N-2-acetylaminophenanthrene. 1977

M C Lang, and R P Fuchs, and M P Daune

The acetic acid ester of the proximate carcinogen N-hydroxy-N-2-acetylaminophenanthrene was reacted in vitro with native and heat-denatured calf thymus DNA under various conditions. We showed that besides the phenanthrylation of the DNA bases there is an acetylation reaction of the DNA during its reaction with the ultimate carcinogen. Heat-denatured DNA is 5 to 10 times more acetylated than native DNA. This result suggests that most of the acetylation sites are nonreactive in the double-helical structure of DNA. On the other hand, the phenanthrylation of the bases is shown not to depend on the DNA secondary structure, suggesting that the phenanthrylation sites of the bases are accessible in the grooves of the DNA double helix. The influence of the DNA dynamic structure on the reactions of acetylation and phenanthrylation has been investigated by increasing the ionic strength of the incubation buffer. The melting temperature of different DNA samples, which have been reacted with different concentrations of N-acetoxy-N-2-acetylaminophenanthrene, decreases as the extent of the DNA modifications increases. This thermal destabilization of the double helix is tentatively attributed to the phenanthrylation rather than to the acetylation reaction.

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
D009691	Nucleic Acid Denaturation	Disruption of the secondary structure of nucleic acids by heat, extreme pH or chemical treatment. Double strand DNA is "melted" by dissociation of the non-covalent hydrogen bonds and hydrophobic interactions. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible.	DNA Denaturation,DNA Melting,RNA Denaturation,Acid Denaturation, Nucleic,Denaturation, DNA,Denaturation, Nucleic Acid,Denaturation, RNA,Nucleic Acid Denaturations
D010616	Phenanthrenes	POLYCYCLIC AROMATIC HYDROCARBONS composed of three fused BENZENE rings.
D002273	Carcinogens	Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.	Carcinogen,Oncogen,Oncogens,Tumor Initiator,Tumor Initiators,Tumor Promoter,Tumor Promoters,Initiator, Tumor,Initiators, Tumor,Promoter, Tumor,Promoters, Tumor
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
D006147	Guanine
D000107	Acetylation	Formation of an acetyl derivative. (Stedman, 25th ed)	Acetylations
D000225	Adenine	A purine base and a fundamental unit of ADENINE NUCLEOTIDES.	Vitamin B 4,4, Vitamin B,B 4, Vitamin
D013816	Thermodynamics	A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)	Thermodynamic
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In