Biomaterial Database

Conformational changes of nucleic acids and poly (d(A-T)-d(A-T)) caused by photoaddition of furocoumarins. 1976

L Kittler, and C Zimmer

DNA's of various AT content, poly[d(A-T)-d(A-T)], and double-stranded RNA were irradiated with UV light at 365 nm in the presence of linear (xanthotoxin) or angular (angelicin) furocoumarins. The covalent photobinding is strongly dependent on the spatial arrangement of furocoumarin molecules at the polymer conformation. CD measurements demonstrate that the bifunctional photochemical binding of xanthotoxin with double-stranded DNA's and poly[d(A-T)-d(A-T)] is accompanied by conformational changes which involve probably decreasing helical twisting of the double helix. This effect is greatly enhanced with increasing AT content. The formation of A-like structures is very unlikely since the B leads to A transition induced by ethanol addition was found to be strongly suppressed in xanthotoxin photoreacted DNA. The B-type helix appears to be the most sensitive conformation with minor restriction to produce photochemically induced cross-links.

UI	MeSH Term	Description	Entries
D007536	Isomerism	The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Isomerisms
D008730	Methoxsalen	A naturally occurring furocoumarin compound found in several species of plants, including Psoralea corylifolia. It is a photoactive substance that forms DNA ADDUCTS in the presence of ultraviolet A irradiation.	8-Methoxypsoralen,Ammoidin,Xanthotoxin,8-MOP,Deltasoralen,Dermox,Geroxalen,Meladinina,Meladinine,Meloxine,Methoxa-Dome,Méladinine,Oxsoralen,Oxsoralen-Ultra,Puvalen,Ultramop,8 MOP,8 Methoxypsoralen,8MOP,Methoxa Dome,Oxsoralen Ultra
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
D011119	Polynucleotides	BIOPOLYMERS composed of NUCLEOTIDES covalently bonded in a chain. The most common examples are DNA and RNA chains.	Polynucleotide
D011564	Furocoumarins	Polycyclic compounds consisting of a furan ring fused with coumarin. They commonly occur in PLANTS, especially UMBELLIFERAE and RUTACEAE, as well as PSORALEA.	Furanocoumarin,Furanocoumarins,Furocoumarin,Psoralens,Angelicins
D011830	Radiation Effects	The effects of ionizing and nonionizing radiation upon living organisms, organs and tissues, and their constituents, and upon physiologic processes. It includes the effect of irradiation on food, drugs, and chemicals.	Effects, Radiation,Effect, Radiation,Radiation Effect
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
D003374	Coumarins	Synthetic or naturally occurring substances related to coumarin, the delta-lactone of coumarinic acid.	1,2-Benzopyrone Derivatives,1,2-Benzopyrones,Coumarin Derivative,Coumarine,1,2-Benzo-Pyrones,Benzopyran-2-ones,Coumarin Derivatives,Coumarines,1,2 Benzo Pyrones,1,2 Benzopyrone Derivatives,1,2 Benzopyrones,Benzopyran 2 ones,Derivative, Coumarin,Derivatives, 1,2-Benzopyrone,Derivatives, Coumarin
D003854	Deoxyribonucleotides	A purine or pyrimidine base bonded to a DEOXYRIBOSE containing a bond to a phosphate group.	Deoxyribonucleotide