Aureochrome (Aureo) is a recently discovered blue light sensor protein initially from Vaucheria frigida, in which it controls blue light-dependent branch formation and/or development of a sex organ by a light-dependent change in the affinity for DNA. Although photochemical reactions of Aureo-LOV (LOV is a C-terminal light-oxygen-voltage domain) and the N-terminal truncated construct containing a bZIP (N-terminal basic leucine zipper domain) and a LOV domain have previously been reported, the reaction kinetics of the change in affinity for DNA have never been elucidated. The reactions of Aureo where the cysteines are replaced by serines (AureoCS) as well as the kinetics of the change in affinity for a target DNA are investigated in the time-domain. The dimerization rate constant is obtained as 2.8 × 10(4) M(-1) s(-1), which suggests that the photoinduced dimerization occurs in the LOV domain and the bZIP domain dimerizes using the interaction with DNA. Surprisingly, binding with the target DNA is completed very quickly, 7.7 × 10(4) M(-1) s(-1), which is faster than the protein dimerization rate. It is proposed that the nonspecific electrostatic interaction, which is observed as a weak binding with DNA, may play a role in the efficient searching for the target sequence within the DNA.

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We synthesized a pair of A–D–A–D–A (A = acceptor, D = donor unit) oligomers containing a benzothiadiazole (BT) unit, namely, DRCN5BT-HH and DRCN5BT-TT, which differs in the positions of alkyl side chains. Solution-processed bulk heterojunction solar cells consisting of PC61BM and DRCN5BT-HH gave a high Voc of 1.10 V and markedly improved power conversion efficiencies up to 3.26% after solvent vapor annealing (SVA). The effects of SVA on the morphology and microstructure of the active layer were investigated by atomic force microscopy (AFM) and grazing-incidence wide angle X-ray scattering (GIWAXS). For DRCN5BT-HH, crystallization, orientation, and molecular ordering were improved, and a fibrillar structure was formed with acicular aggregates of the donor. For DRCN5BT-TT, no marked structural changes were induced by SVA. We found that these morphological and microstructural changes induced by SVA correlate with the differences in the photovoltaic properties of both of the isomers.

A new approach for the preparation of poly (para-phenylenevinylene) (PPV) with an ordered structure is presented. PPV is synthesized by a precursor method using a cholesteric liquid crystal medium. The resultant PPV film is observed to have a cholesteric fingerprint-like texture, indicating replication of the cholesteric liquid crystal medium. Infrared absorption measurements confirm that the PPV has essentially the same molecular structure as normal PPV film. Ultraviolet-visible absorption measurements show that the absorption band due to p2p* transition of the conjugated main-chain is located at 402 nm. The conversion is found to occur at the interface with the cholesteric liquid crystal medium as a mechanical process.

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