Lefevre J F, Lane A N, Jardetzky O
FEBS Lett. 1985 Oct 7;190(1):37-40. doi: 10.1016/0014-5793(85)80422-1.
Proton NMR spectra of the trp operator-promoter (sequence CGTACTAGTT.AACTAGTACG) show selective changes in chemical shift and relaxation rates over the range of temperature 0-45 degrees C for the non-exchangeable protons of A11 and A12 only. These bases are in the centre of the Pribnow box. The changes imply that at least three conformational states become significantly populated in this range of temperature, and probably involve a change in the propellor twists of A11 and A12 for one transition, and changes in the helical twist and local pitch for the other. As (1) mutations in the Pribnow box that destroy the TAA sequence impair promoter activity, and (2) the abortive initiation assay for RNA polymerase shows a transition near 20 degrees C, we propose that the observed conformational transitions in the trp promoter are an essential feature of good promoters.
色氨酸操纵子启动子（序列CGTACTAGTT.AACTAGTACG）的质子核磁共振谱显示，仅A11和A12的不可交换质子在0至45摄氏度的温度范围内化学位移和弛豫速率有选择性变化。这些碱基位于Pribnow框的中心。这些变化表明，在该温度范围内至少有三种构象状态变得显著丰富，并且可能涉及一次转变中A11和A12的螺旋桨扭转变化，以及另一次转变中螺旋扭转和局部螺距的变化。由于（1）破坏TAA序列的Pribnow框中的突变会损害启动子活性，以及（2）RNA聚合酶的流产起始测定显示在20摄氏度附近有一个转变，我们提出在色氨酸启动子中观察到的构象转变是良好启动子的一个基本特征。
