Hung Chih-Chang, Yabushita Atsushi, Kobayashi Takayoshi, Chen Pei-Feng, Liang Keng S
Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan.
Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan; Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Yokohama 221-8686, Japan; CREST, JST, Saitama, Japan.
Biophys Chem. 2016 Jul-Aug;214-215:11-6. doi: 10.1016/j.bpc.2016.05.001. Epub 2016 May 10.
Ultrafast transient absorption spectroscopy of endothelial NOS oxygenase domain (eNOS-oxy) was performed to study dynamics of ligand or substrate interaction under Soret band excitation. Photo-excitation dissociates imidazole ligand in <300fs, then followed by vibrational cooling and recombination within 2ps. Such impulsive bond breaking and late rebinding generate proteinquakes, which relaxes in several tens of picoseconds. The photo excited dynamics of eNOS-oxy with L-arginine substrate mainly occurs at the local site of heme, including ultrafast internal conversion within 400fs, vibrational cooling, charge transfer, and complete ground-state recovery within 1.4ps. The eNOS-oxy without additive is partially bound with water molecule, thus its photoexcited dynamics also shows ligand dissociation in <800fs. Then it followed by vibrational cooling coupled with charge transfer in 4.8ps, and recombination of ligand to distal side of heme in 12ps.
采用超快瞬态吸收光谱法研究内皮型一氧化氮合酶加氧酶结构域（eNOS-oxy）在索雷特带激发下配体或底物相互作用的动力学。光激发在<300飞秒内使咪唑配体解离，随后在2皮秒内进行振动冷却和重新结合。这种脉冲式的键断裂和后期重新结合会产生蛋白质振动，在几十皮秒内弛豫。eNOS-oxy与L-精氨酸底物的光激发动力学主要发生在血红素的局部位点，包括在400飞秒内的超快内转换、振动冷却、电荷转移以及在1.4皮秒内完全恢复基态。未添加添加剂的eNOS-oxy与水分子部分结合，因此其光激发动力学也显示在<800飞秒内配体解离。然后在4.8皮秒内进行振动冷却并伴随电荷转移，在12皮秒内配体重新结合到血红素的远端。
