NUCLEAR MAGNETIC RESONANCE--NEW METHODS AND MOLECULAR STRUCTURE DETERMINATION

本文报道了一氧化碳肌球蛋白的Fe57核磁共振波谱。这是 蛋白质的第一次Fe57核磁共振研究。 一种新的二维(2D)核磁共振技术已经被开发出来 同核耦合自旋系统中自旋连接性的测定。 新方法依赖于一种与所有其他2D方法不同的机制 技术，并具有许多优势：净磁化 获得耦合自旋之间的转移，这允许记录 高分辨率吸收模式光谱，并提供更高的灵敏度。 通过明智地选择混合，可以观察到中继连接 句号。初步的实验结果，得出了一些小的 蛋白质(溶菌酶、核糖核酸酶、牛胰蛋白酶抑制剂和肌红蛋白) 表明该方法优于现有的竞争性技术。 该方法对于H1中的共振赋值也非常有用 低聚糖等有机产物的复数核磁共振波谱 光谱。 对现有一维和二维实验的一些改进 已经提出了优化标准，并且已经为三个 相当复杂的2D实验：(A)同核接力相干转移 光谱学，(B)异核接力光谱学和(C)自旋锁定NOE 测量。 新的核磁共振技术已经被用来确定以前未知的 四烯类抗生素两性霉素A的结构。

The Fe57 NMR spectrum of carbonmonoxymyoglobin has been reported. This is the first Fe57 NMR study of a protein. A new two-dimensional (2D) NMR technique has been developed for the determination of spin connectivity in homonuclear coupled spin systems. The new method relies on a different mechanism than all other 2D techniques, and has a significant number of advantages: net magnetization transfer between coupled spins is obtained which permits the recording of high resolution absorption mode spectra and provides improved sensitivity. Relayed connectivity can be observed by a judicious choice of the mixing period. Preliminary experimental results, obtained for a number of small proteins (lysozyme, ribonuclease, bovine trypsin inhibitor and myoglobin) suggest that the method is superior to existing competitive techniques. The method appears also very useful for the resonance assignment in H1 spectra of oligosaccharides and other organic products with complex NMR spectra. A number of improvements for existing one- and two-dimensional experiments have been proposed and optimization criteria have been developed for three rather complex 2D experiments: (a) homonuclear relayed coherence transfer spectroscopy, (b) heteronuclear relay spectroscopy and (c) spin-locked NOE measurements. New NMR techniques have been used to determine the previously unknown structure of the tetraene antibiotic, amphotericin A.