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sensitivity to the action of radiant energy (同)radiosensitivity

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感光性の

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1. 日焼け止めおよび太陽光線からの保護法の選択 selection of sunscreen and sun protective measures

English Journal

Concurrent Block Copolymer Polymersome Stabilization and Bilayer Permeabilization by Stimuli-Regulated "Traceless" Crosslinking.

Wang X, Liu G, Hu J, Zhang G, Liu S.Author information CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical, Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China).AbstractThe fabrication of block copolymer (BCP) vesicles (polymersomes) exhibiting synchronized covalent crosslinking and bilayer permeabilization remains a considerable challenge as crosslinking typically leads to compromised membrane permeability. Herein it is demonstrated how to solve this dilemma by employing a stimuli-triggered crosslinking strategy with amphiphilic BCPs containing photolabile carbamate-caged primary amines. Upon self-assembling into polymersomes, light-triggered self-immolative decaging reactions release primary amine moieties and extensive amidation reactions then occur due to suppressed amine pKa within hydrophobic milieu. This leads to serendipitous vesicle crosslinking and the process is associated with bilayer hydrophobicity-to-hydrophilicity transition and membrane permeabilization.
Angewandte Chemie (International ed. in English).Angew Chem Int Ed Engl.2014 Feb 12. doi: 10.1002/anie.201310589. [Epub ahead of print]
The fabrication of block copolymer (BCP) vesicles (polymersomes) exhibiting synchronized covalent crosslinking and bilayer permeabilization remains a considerable challenge as crosslinking typically leads to compromised membrane permeability. Herein it is demonstrated how to solve this dilemma by em
PMID 24519898

Aggregation Gatekeeper and Controlled Assembly of Trpzip β-Hairpins.

Markiewicz BN, Oyola R, Du D, Gai F.Author information Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.AbstractProtein and peptide aggregation is an important issue both in vivo and in vitro. Herein, we examine the aggregation behaviors of two well-studied β-hairpins, Trpzip1 and Trpzip2. Previous studies suggested that Trpzip2 remains monomeric up to a concentration of ∼15 mM whereas Trpzip1 readily aggregates at micromolar concentrations at acidic or neutral pH. This disparity is puzzling considering that these two peptides differ only in their turn sequences (i.e., GN vs NG). We hypothesize that these peptides can aggregate from their folded states via native edge-to-edge interactions and that the Lys8 residue in Trpzip2 is a more effective aggregation gatekeeper, because of a more favorable orientation. In support of this hypothesis, we find that increasing the pH to 13 or replacing Lys8 with a hydrophobic and photolabile Lys analogue, Lys(nvoc), leads to a significant increase in the aggregation propensity of Trpzip2, and that the aggregation of this Trpzip2 mutant can be reversed upon restoring the native Lys side chain via photocleavage of the nvoc moiety. In addition, we find that while both Trpzip1 and Trpzip2 form parallel β-sheet aggregates, the Lys(nvoc) Trpzip2 mutant forms antiparallel β-sheets and more stable fibrils. Taken together, these findings provide another example showing how sensitive peptide and protein aggregation is to minor sequence variation and that it is possible to use a photolabile non-natural amino acid, such as Lys(nvoc), to tune the rate of peptide aggregation and to control fibrillar structure.
Biochemistry.Biochemistry.2014 Feb 12. [Epub ahead of print]
Protein and peptide aggregation is an important issue both in vivo and in vitro. Herein, we examine the aggregation behaviors of two well-studied β-hairpins, Trpzip1 and Trpzip2. Previous studies suggested that Trpzip2 remains monomeric up to a concentration of ∼15 mM whereas Trpzip1 readily aggr
PMID 24498924

Mechanism of the Photoinduced Uncaging Reaction of Puromycin Protected by a 6-Nitroveratryloxycarbonyl Group.

Kohl-Landgraf J, Buhr F, Lefrancois D, Mewes JM, Schwalbe H, Dreuw A, Wachtveitl JL.AbstractThe cleavage of a photolabile nitroveratryloxycarbonyl protecting group (NVOC), which is widely used as caging group, was studied by femtosecond-transient absorption spectroscopy in the visible and infrared spectral range and by flash-photolysis experiments on the longer time scale. Based on quantum chemical calculations it is shown that directly after excitation triplet absorption dominates the transient spectrum which is not part of the reactive pathway and that the molecules following the triplet pathway are trapped in a non-reactive triplet state. By contrast photolysis proceeds from the singlet manifold. Therefore trapping in the triplet state lowers the quantum yield of the process for this compound compared to other ortho-nitrobenzyl protecting groups. With our integrated approach of time-resolved UV and IR measurements and calculations we can characterize the entire uncaging mechanism and identify the most relevant intermediate states along the reaction pathway. The final uncaging is accomplished within 32 µs.
Journal of the American Chemical Society.J Am Chem Soc.2014 Feb 11. [Epub ahead of print]
The cleavage of a photolabile nitroveratryloxycarbonyl protecting group (NVOC), which is widely used as caging group, was studied by femtosecond-transient absorption spectroscopy in the visible and infrared spectral range and by flash-photolysis experiments on the longer time scale. Based on quantum
PMID 24517286

Japanese Journal

Polymerization and Photodegradation of Crosslinkers Bearing Photolabile O-Methacryloyloxime Moieties

Suyama Kanji,Tachi Hideki
Journal of Photopolymer Science and Technology 27(2), 231-232, 2014
… TBzM and DBzM were newly prepared as novel photolabile crosslinkers. …
NAID 130004678345

Comparative Study on the Photostability of Arbutin and Deoxy Arbutin: Sensitivity to Ultraviolet Radiation and Enhanced Photostability by the Water-Soluble Sunscreen, Benzophenone-4

YANG Chao-Hsun,CHANG Nai-Fang,CHEN Yi-Shyan,LEE Shu-Mei,LIN Pei-Jin,LIN Chih-Chien
Bioscience, Biotechnology, and Biochemistry 77(5), 1127-1130, 2013
… The results revealed arbutin and deoxy arbutin to be photolabile in an aqueous solution. …
NAID 130004054104

2-(N-Acyl-N-carboxymethylamino)-1-nitrodibenzo[b,d]thiophene: A New Class of Caging Group for Environmental Selective Photorelease of Carboxylic Acid

Tanaka Yuji,Momotake Atsuya,Arai Tatsuo
Chemistry Letters 41(6), 642-643, 2012
… The new environment sensitive photolabile protecting group, N-carboxymethyl-1-nitrodibenzo[b,d]thiophen-2-ylamino (CNDT) group, is described. …
NAID 130004426596