Orekhov V Y, Dubovskii P V, Yamada H, Akasaka K, Arseniev A S
Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
J Biomol NMR. 2000 Jul;17(3):257-63. doi: 10.1023/a:1008346414720.
Dynamics and structure of (1-36)bacteriorhodopsin solubilized in chloroform/methanol mixture (1:1) were investigated by 1H-15N NMR spectroscopy under a hydrostatic pressure of 2000 bar. It was shown that the peptide retains its spatial structure at high pressure. 15N transverse and longitudinal relaxation times, 15N[1H] nuclear Overhauser effects, chemical shifts and the translation diffusion rate of the peptide at 2000 bar were compared with the respective data at ambient pressure [Orekhov et al. (1999) J. Biomol. NMR, 14, 345-356]. The model free analysis of the relaxation data for the helical 9-31 fragment revealed that the high pressure decreases the overall rotation and translation diffusion, as well as apparent order parameters of fast picosecond internal motions (S2) but has no effect on internal nanosecond motions (S2 and taus) of the peptide. The decrease of translation and overall rotation diffusion was attributed to the increase in solvent viscosity and the decrease of apparent order parameters S2f to a compression of hydrogen bonds. It is suggested that this compression causes an elongation of H-N bonds and a decrease of absolute values of chemical shift anisotropy (CSA). In particular, the observed decrease of S2f at 2000 bar can be explained by 0.001 nm increase of N-H bond lengths and 10 ppm decrease of 15N CSA values.
在2000巴的静水压力下，通过1H-15N核磁共振光谱研究了溶解于氯仿/甲醇混合物（1:1）中的（1-36）细菌视紫红质的动力学和结构。结果表明，该肽在高压下保持其空间结构。将2000巴下该肽的15N横向和纵向弛豫时间、15N[1H]核Overhauser效应、化学位移及平移扩散速率与常压下的相应数据进行了比较[奥列霍夫等人（1999年）《生物分子核磁共振杂志》，第14卷，第345 - 356页]。对螺旋9 - 31片段弛豫数据的无模型分析表明，高压降低了整体旋转和平移扩散，以及快速皮秒内运动的表观序参数（S₂），但对该肽的纳秒内运动（S₂和弛豫时间常数）没有影响。平移和整体旋转扩散的降低归因于溶剂粘度的增加，而表观序参数S₂f的降低归因于氢键的压缩。据推测这种压缩导致H - N键伸长以及化学位移各向异性（CSA）绝对值减小。特别地，在2000巴下观察到的S₂f降低可以用N - H键长度增加0.001纳米以及15N CSA值降低10 ppm来解释。
