A procedure for covalent binding of DNA to a functionalized mica substrate is described. The approach is based on photochemical cross-linking of DNA to immobilized psoralen derivatives. A tetrafluorphenyl (TFP) ester of trimethyl psoralen (trioxalen) was synthesized, and the procedure to immobilize it onto a functionalized aminopropyl mica surface (AP-mica) was developed. DNA molecules were cro...

The location of proteins on the mitochondrial DNA (mtDNA) of Drosophila virilis was investigated by Me3 psoralen photoreaction of mitochondria isolated from embryos. After photoreaction the mtDNA was purified and the pattern of DNA cross-linking was determined by electron microscopy of the DNA under totally denaturing conditions. The transcribed regions of the mtDNA molecule contained some uncr...

The psoralen compounds, xanthotoxin and 4,5', 8-trimethylpsoralen, when activated, increased phenylalanine ammonia lyase (PAL) activity and the synthesis of pisatin in excised pea pods. Pods presoaked 1 hr with 4,5',8-trimethylpsoralen and then irradiated 4 minutes with 366 nanometer ultraviolet light had twice as much PAL activity 3 hours after irradiation and 12 times as much PAL activity 20 ...

T2 bacteriophage sensitization has been studied using two furocoumarins capable of linking covalently to DNA to the same extent but producing different damages, psoralen and 4,5'-dimethylangelicin. Psoralen is a well-known linear furocoumarin capable of inducing in DNA both monoadducts and cross-links; 4,5'-dimethylangelicin is a new angular compound known as a pure monofunctional reagent. In t...

Psoralea corylifolia (P. corylifolia) is a medicinal plant used primarily in herbal dietary supplements to treat skin diseases, such as vitiligo and psoriasis. Case reports of liver toxicity have recently emerged from its use, which often includes co-administration with other herbal products. In this study, CYP3A4 inhibition and hepatotoxicity of P. corylifolia and its major components were eva...

The three La Crosse virus genomes are found as circular structures in the electron microscope, and the RNA ends of at least the small (S) and medium (M) segments are highly complementary. When examined for psoralen cross-linking, about half of the S, at most 1 to 2% of the M, and none of the large (L) nucleocapsid RNAs could be cross-linked in virions or at late times intracellularly, under con...

Angelicae Pubescentis Radix (APR) is a widely-used traditional Chinese medicine. Pharmacological studies have begun to probe its biological activities on neurological disorders recently. To assess the brain penetration and distribution of APR, a validated ultra-performance liquid chromatography tandem mass spectrometry method was applied to the simultaneous determinations of the main coumarins ...

MUS81-EME1 is a DNA endonuclease involved in replication-coupled repair of DNA interstrand cross-links (ICLs). A prevalent hypothetical role of MUS81-EME1 in ICL repair is to unhook the damage by incising the leading strand at the 3' side of an ICL lesion. In this study, we report that purified MUS81-EME1 incises DNA at the 5' side of a psoralen ICL residing in fork structures. Intriguingly, IC...

The in vivo association with proteins of HeLa cell mitochondrial DNA (mtDNA) has been investigated by analyzing the pattern of in situ crosslinking of the DNA by 4'-hydroxymethyl-4, 5',8-trimethylpsoralen (HMT). Either isolated mitochondria or whole cells were irradiated with long wavelength UV light in the presence of ths psoralen derivative, and the mtDNA was then isolated and analyzed in the...