Structural Analysis of Intact Biomolecules by Solid State High Resolution Nuclear Magnetic Resonance with Homogenously Isotope Labeled Samples

我们建立了用同质同位素标记样品的固体高分辨核磁共振(NMR)分析完整生物分子结构的系统。该系统已应用于紫色光合细菌的膜天线LH1和绿色光合细菌的绿体天线。通过用同位素富集物配制的培养基对细菌进行培养，得到均一的同位素标记样品。用高分辨核磁共振仪初步研究了膜天线LH1在去中性洗涤剂辛基-β-D-吡喃葡萄糖苷中的作用。由于同位素浓缩的影响，许多核磁共振信号被解析和指认为细菌叶绿素a。用我们发现的溶剂汽化法制备了同位素标记的细菌叶绿素c的模型绿小体。将这些系统应用于模型绿小体，发现了高分辨率的信号，每个信号都成对出现。这意味着绿小体是由基本的二聚体组成的，或者以两种截然不同的构象存在。

We have established the system for the structural analysis of intact biomolecules by solid state high resolution nuclear magnetic resonance (NMR) with homogenously isotope labeled samples. The system was applied to the membrane antenna LH1 of purple photosynthetic bacteria, and to the chlorosome antenna of green photosynthetic bacteria. The homogenously isotope labeled samples were obtained by cultivation of the bacteria with medium prepared with isotope enriched compounds. The membrane antennae LH1 was preliminary investigated by high resolution NMR in the solution dissolved in deutrated detergent, octyl-β-D-glucopyranoside. Many NMR signals were resolved and assigned for bacteriochlorophyll a due to the effects of the isotope enrichment. The model chlorosomes have been prepared with the isotope labeled bacteriochlorophyll c by the solvent vaporization method found by us. Application of the systems to the model chlorosomes revealed highly resolved signal, each of which appeared in pairwise. This implied that the chlorosomes are composed basic dimmer building block, or exist as two distinctly different conformations.