青色光センタータンパク質の光反応ダイナミクスとCrowding環境への発展

京都大学0048新制・課程博士博士(理学)甲第15892号理博第3633号新制||理||1529(附属図書館)28471京都大学大学院理学研究科化学専攻(主査)教授 寺嶋 正秀, 教授 竹腰 清乃理, 教授 松本 吉泰学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDA

Macromolecular crowding effects on reactions of TePixD (Tll0078).

To reveal macromolecular crowding effects on a chemical reaction of a BLUF (sensors of blue light using FAD) protein (PixD from a thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 [TePixD, Tll0078]), the photoreaction was studied at various concentrations of the macromolecule Ficoll-70 by UV/Vis absorption spectroscopy and the pulsed laser-induced transient grating (TG) method. The absorption spectrum did not change with varying concentration of Ficoll-70. The crowding did not affect the quantum yield of the spectral red shift reaction, recovery rate of the product, rate constant of the volume change reaction and the magnitude of the volume change. However, the magnitude of the TG signal representing the diffusion-sensitive conformation change significantly increased on addition of Ficoll-70. This dependence was attributed to the crowding effect on the TePixD decamer-pentamer equilibrium in the solution. This result indicates that the TePixD reaction is more efficient in cellular than in in vitro conditions

The Use of Information and Communication Technology–Based Self-management System DialBeticsLite in Treating Abdominal Obesity in Japanese Office Workers: Prospective Single-Arm Pilot Intervention Study

BackgroundMaking lifestyle changes is an essential element of abdominal obesity (AO) reduction. To support lifestyle modification and self-management, we developed an information and communication technology–based self-management system—DialBeticsLite—with a fully automated dietary evaluation function for the treatment of AO. ObjectiveThe objective of this study was to evaluate the preliminary efficacy and feasibility of DialBeticsLite among Japanese office workers with AO. MethodsA 2- to 3-month prospective single-arm pilot intervention study was designed to assess the effects of the intervention using DialBeticsLite. The information and communication technology system was composed of 4 modules: data transmission (body weight, blood pressure, blood glucose, and pedometer count); data evaluation; exercise input; and food recording and dietary evaluation. Eligible participants were workers who were aged ≥20 years and with AO (waist circumference ≥85 cm for men and ≥90 cm for women). Physical parameters, blood tests, nutritional intake, and self-care behavior were compared at baseline and after the intervention. ResultsA total of 48 participants provided completed data for analysis, which yielded a study retention rate of 100%. The average age was 46.8 (SD 6.8) years, and 92% (44/48) of participants were male. The overall average measurement rate of DialBeticsLite, calculated by dividing the number of days with at least one measurement by the number of days of the intervention, was 98.6% (SD 3.4%). In total, 85% (41/48) of the participants reported that their participation in the study helped them to improve their lifestyle. BMI, waist circumference, and visceral fat area decreased significantly after the intervention (P<.001). In addition, the daily calorie intake reduced significantly (P=.02). There was a significant improvement in self-care behavior in terms of exercise and diet (P=.001). ConclusionsUsing DialBeticsLite was shown to be a feasible and potentially effective method for reducing AO by providing users with a motivational framework to evaluate their lifestyle behaviors

Photoreactions of Aureochrome-1

Aureochrome is a recently discovered blue light photosensor that controls a light-dependent morphology change. As a photosensor, it has a unique DNA binding domain (bZIP). Although the biological functions of aureochrome have been revealed, the fundamental photochemistry of this protein has not been elucidated. The photochemical reaction dynamics of the LOV (light, oxygen, or voltage) domain of aureochrome-1 (AUREO1-LOV) and the LOV domain with the bZIP domain (AUREO1-ZL) were studied by employing the transient-grating (TG) technique, using size-exclusion chromatography to verify results. For both samples, adduct formation takes place with a time constant of 2.8 μs. Although significant diffusion changes were observed for both AUREO1-LOV and AUREO1-ZL after adduct formation, the origins of these changes were significantly different. The TG signal of AUREO1-LOV was strongly concentration-dependent. From analysis of the signal, it was concluded that AUREO1-LOV exists in equilibrium between the monomer and dimer, and dimerization of the monomer is the main reaction, i.e., irradiation with blue light enhances the strength of the interdomain interaction. On the other hand, the reaction of AUREO1-ZL is independent of concentration, suggesting that an intraprotein conformational change occurs in the bZIP domain with a time constant of 160 ms. These results revealed the different reactions and roles of the two domains; the LOV domain acts as a photosensor, leading to a subsequent conformational change in the bZIP domain, which should change its ability to bind to DNA. A model is proposed that demonstrates how aureochrome uses blue light to control its affinity for DNA