Dalgarno D C, Slater L, Chackalamannil S, Senior M M
Schering-Plough Research Institute, Bloomfield, New Jersey.
Int J Pept Protein Res. 1992 Dec;40(6):515-23. doi: 10.1111/j.1399-3011.1992.tb00435.x.
Two-dimensional NMR techniques were utilized to determine the secondary structural elements of endothelin-1 (ET-1), a potent vasoconstrictor peptide, and two of its point mutants, Met-7 to Ala-7 (ETM7A), and Asp-8 to Ala-8 (ETD8A) in acetic acid-d3/water solution. Sequence specific NMR assignments were determined for all three peptides, as well as chemical shifts and NOE connectivity patterns. The chemical shifts of ET-1 and ETM7A are identical (+/- 0.05 ppm) except for the site of substitution, whereas marked shift changes were detected between ET-1 and ETD8A. These chemical shift differences imply that the Asp-8 to Ala-8 mutation has induced a conformational change relative to the parent conformation. All three molecules show the same basic nuclear Overhauser effect (NOE) pattern, which suggests that the gross conformation of all three molecules is the same. Small changes in sequential NOE intensities and changes in medium-range NOE patterns indicate that there are subtle conformational differences between ET-1 and ETD8A.
利用二维核磁共振技术，在乙酸-d3/水溶液中测定了强效血管收缩肽内皮素-1（ET-1）及其两个点突变体，即第7位甲硫氨酸突变为丙氨酸（ETM7A）和第8位天冬氨酸突变为丙氨酸（ETD8A）的二级结构元件。确定了所有三种肽的序列特异性核磁共振归属，以及化学位移和核Overhauser效应（NOE）连接模式。除了取代位点外，ET-1和ETM7A的化学位移相同（±0.05 ppm），而在ET-1和ETD8A之间检测到明显的位移变化。这些化学位移差异表明，第8位天冬氨酸突变为丙氨酸的突变相对于亲本构象诱导了构象变化。所有三个分子都显示出相同的基本核Overhauser效应（NOE）模式，这表明所有三个分子的总体构象相同。顺序NOE强度的微小变化和中程NOE模式的变化表明，ET-1和ETD8A之间存在细微的构象差异。
