DNA photolyases catalyze the splitting of the cyclobutane ring joining the two dihydropyrimidines of a pyrimidine dimer by a photoinduced electron-transfer reaction. Previous studies concluded that photolyase repairs only the cis-syn form of the eight stereoisomers of the cyclobutane pyrimidine dimer (Pyr[ ]Pyr). In this study we found that Escherichia coli photolyase binds to the trans-syn-I i...

Lycopene is present mainly as cis-isomers in human serum and tissues whereas all-trans-lycopene predominates in tomato products, suggesting that all-trans-lycopene is isomerised in the body or is less bioavailable. The objectives of the present study were to develop processing conditions for tomatoes to obtain products with different cis-trans-lycopene isomer distribution and to assess their bi...

ras proto-oncogenes with a cyclobutane-type thymine photodimer (cis-syn or trans-syn isomer) were constructed by replacement of a portion of the gene with a chemically synthesized fragment. When the genes were transfected by the calcium phosphate method into mouse NIH3T3 cells, they induced focus-formation, indicating that both photoproducts were mutagenic in mammalian cells. Sequence analysis ...

The dynamics of ferulic acid (3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid) and caffeic acid (3-(3,4-dihydroxyphenyl)-2-propenoic acid) in acetonitrile, dioxane and water at pH 2.2 following photoexcitation to the first excited singlet state are reported. These hydroxycinnamic acids display both strong ultraviolet absorption and potent antioxidant activity, making them promising sunscreen com...

cis-trans isomerization of proteins phosphorylated by proline-directed kinases is proposed to control numerous signaling molecules and is implicated in the pathogenesis of Alzheimer's and other diseases. However, there is no direct evidence for the existence of cis-trans protein isomers in vivo or for their conformation-specific function or regulation. Here we develop peptide chemistries that a...

The process called biohydrogenation occurs mainly in ruminant animals and during it, unsaturated fatty acids, and particularly poly-unsaturated ones (linoleic and linolenic) coverts to a saturated form of stearic acid. For many years, the beneficial effects of biohydrogenation intermediate fatty acids like cis-9 trans-11 linoleic acid, the main natural isomer of conjugated linoleic acids (CLA),...

The effects of conjugated linoleic acid isomers (CLA) and endurance training on lean body mass are expected to result from their action on tissue protein metabolism. The aim of this study was to analyze their effects on protein metabolism in 2 muscles, the small intestine and liver of adult rats. Four-month-old male Wistar rats were fed diets containing either no CLA, cis-9, trans-11 CLA isomer...

We have found that in addition to the 11-cis and 9-cis isomers of retinal which are known to couple with the visual pigment apoprotein opsin to form pigments, a third isomer 9,13-dicis retinal also will form a pigment. That this isomer is indeed bound to opsin has been shown unequivocally by removing the chromophore without isomerization and subsequent identification by high-speed liquid chroma...

We have made a diffraction grating in an indoline azobenzene/amorphous polycarbonate film by two-beam interference at 532 nm that periodically photodegrades the indoline azobenzene dye. Subsequent illumination of the film with 532-nm light into the trans-isomer band leads to trans-cis isomerization in the indoline azobenzene dye and results in a decrease in the trans-isomer band absorption coef...

Photoresponsive systems for site-selective RNA scission have been prepared by combining Lu(III) ions with acridine/azobenzene dual-modified DNA. The modified DNA forms a heteroduplex with substrate RNA, and the target phosphodiester linkages in front of the acridine residue is selectively activated so that Lu(III) ion rapidly cleaves the linkage. Azobenzene residue introduced adjacent to the ac...