Römer R, Varadi V
Proc Natl Acad Sci U S A. 1977 Apr;74(4):1561-4. doi: 10.1073/pnas.74.4.1561.
Temperature-dependent lowfield proton magnetic resonance spectra of yeast tRNAPhe were recorded between 10 and 15 parts per million. Seven resonances of hydrogen-bonded protons disappeared reversibly under two sets of conditions where the selective broadening of tertiary structure resonances were predicted by temperature jump experiments. The seven resonances were assigned to the seven tertiary hydrogen bonds expected between 10 and 15 parts per million from the crystal structure of yeast tRNAPhe. Some of the non-Watson-Crick base pairs have unusual unshifted standard chemical shifts after the ring current contributions calculated from the crystal coordinates were subtracted. The differences of the chemical shifts of homologous tertiary structure base pairs in Escherichia coli tRNAfMet and yeast tRNAPhe give experimental evidence for details of the conformational differences postulated by model building on the basis of the x-ray coordinates of yeast tRNAPhe and sequence homologies.
在百万分之10至15的范围内记录了酵母苯丙氨酸转运核糖核酸(tRNAPhe)的温度依赖性低场质子磁共振谱。在两组条件下,七个氢键质子的共振可逆消失,这两组条件下通过温度跃升实验预测了三级结构共振的选择性展宽。这七个共振被指定为酵母苯丙氨酸转运核糖核酸晶体结构中百万分之10至15之间预期的七个三级氢键。从晶体坐标计算出的环电流贡献被减去后,一些非沃森-克里克碱基对具有不寻常的未移动标准化学位移。大肠杆菌甲硫氨酸转运核糖核酸(tRNAfMet)和酵母苯丙氨酸转运核糖核酸中同源三级结构碱基对化学位移的差异,为基于酵母苯丙氨酸转运核糖核酸的x射线坐标和序列同源性通过模型构建推测的构象差异细节提供了实验证据。