蛋白质芳香基团的~1H-^(13)C HSQC信号增强研究(英文)

Sensitivity Enhancement in ~1H-^(13)C HSQC Experiments on Aromatic Groups in Proteins

含芳香环的氨基酸残基多处于蛋白质的疏水内核或者是蛋白质与配体的结合部位,这些残基间的非共价键相互作用对于蛋白质结构的稳定性和生物的特异性识别有重要意义.因此,在蛋白质的核磁共振研究中,芳香基团被认为是一个研究蛋白质结构动力学的潜在探针.但是由于芳香基团的1H-13C HSQC谱的灵敏度较低,目前,利用核磁共振对其进行研究乏善可陈.造成这一现象的主要原因可能在于芳香环体积较大,往往存在慢的翻转运动,导致其NMR信号被展宽.作者利用CPMG-INEPT HSQC序列可以有效地减小慢运动影响的特征,将其应用到了GB1蛋白质芳香环的1H-13C HSQC谱中,有效的增强了芳香基团HSQC谱信号的灵敏度,得到了部分在常规HSQC中无法观测的信号.

Aromatic side chains are usually located in the hydrophobic core or ligand binding sites of proteins. They play important roles in protein functions such as structure stabilization and biological recognition through noncovalent interactions. Thus, aromatic side chains are considered to be a promising probe to determine the structure and dynamics of protein through NMR. However, they are not frequently studied in practice. One of the reasons is that some NMR signals of aromatic rings are rarely observed due to the severely line broadening induced by complex slow internal motion. In this study, CPMG-INEPT 1H-13C HSQC was employed to detect the aromatic resonances of protein GB1. It was found that some unobservable peaks in routine 1H-13C HSQC spectrum could be recovered in the corresponding CPMG-1NEPT 1H-13C HSQC spectrum. This indicated that the CPMG-INEPT 1H-13C HSQC may be an effective alternation to routine 1H-13C HSQC for detecting the resonances of aromatic rings in proteins.