当前位置: X-MOL 学术Biochemistry › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Probing the Role of the Heme Distal and Proximal Environment in Ligand Dynamics in the Signal Transducer Protein HemAT by Time-Resolved Step-Scan FTIR and Resonance Raman Spectroscopy
Biochemistry ( IF 2.9 ) Pub Date : 2017-09-21 00:00:00 , DOI: 10.1021/acs.biochem.7b00558
Andrea Pavlou 1 , Andreas Loullis 1 , Hideaki Yoshimura 2 , Shigetoshi Aono 2 , Eftychia Pinakoulaki 1
Affiliation  

HemAT is a heme-containing oxygen sensor protein that controls aerotaxis. Time-resolved step-scan FTIR studies were performed on the isolated sensor domain and full-length HemAT proteins as well as on the Y70F (B-helix), L92A (E-helix), T95A (E-helix), and Y133F (G-helix) mutants to elucidate the effect of the site-specific mutations on the ligand dynamics subsequent to CO photolysis. The mutations aimed to perturb H-bonding and electrostatic interactions near the heme Fe-bound gaseous ligand (CO) and the heme proximal environment. Rebinding of CO to the heme Fe is biphasic in the sensor domain and full-length HemAT as well as in the mutants, with the exception of the Y133F mutant protein. The monophasic rebinding of CO in Y133F suggests that in the absence of the H-bond between Y133 and the heme proximal H123 residue the ligand rebinding process is significantly affected. The role of the proximal environment is also probed by resonance Raman photodissociation experiments, in which the Fe–His mode of the photoproduct of sensor domain HemAT-CO is detected at a frequency higher than that of the deoxy form in the difference resonance Raman spectra. The role of the conformational changes of Y133 (G-helix) and the role of the distal L92 and T95 residues (E-helix) in regulating ligand dynamics in the heme pocket are discussed.

中文翻译:

通过时间分辨步进扫描FTIR和共振拉曼光谱研究血红素远端和近端环境在信号转导蛋白HemAT中的配体动力学中的作用

HemAT是一种控制血流动力学的含血红素的氧传感器蛋白。对分离的传感器结构域和全长HemAT蛋白以及Y70F(B螺旋),L92A(E螺旋),T95A(E螺旋)和Y133F( G-螺旋)突变体,以阐明位点特异性突变对CO光解后配体动力学的影响。突变旨在扰乱血红素结合铁的气态配体(CO)和血红素近端环境附近的H键和静电相互作用。除了Y133F突变蛋白外,CO与血红素Fe的重新结合在传感器域和全长HemAT中以及在突变体中都是双相的。Y133F中CO的单相重新结合表明,在Y133与血红素近端H123残基之间不存在H键的情况下,配体的重新结合过程受到显着影响。共振拉曼光解离实验还探讨了近端环境的作用,其中在差异共振拉曼光谱中以比脱氧形式更高的频率检测到传感器域HemAT-CO的光产物的Fe-His模式。讨论了Y133构象变化的作用(G-螺旋)以及远端L92和T95残基(E-螺旋)在调节血红素袋中配体动力学中的作用。其中,在差分共振拉曼光谱中以高于脱氧形式的频率检测到传感器域HemAT-CO的光产物的Fe-His模式。讨论了Y133构象变化的作用(G-螺旋)以及远端L92和T95残基(E-螺旋)在调节血红素袋中配体动力学中的作用。其中,在差分共振拉曼光谱中以高于脱氧形式的频率检测到传感器域HemAT-CO的光产物的Fe-His模式。讨论了Y133构象变化的作用(G-螺旋)以及远端L92和T95残基(E-螺旋)在调节血红素袋中配体动力学中的作用。
更新日期:2017-09-21
down
wechat
bug