Gohlke C, Murchie A I, Lilley D M, Clegg R M
Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttengen, Federal Republic of Germany.
Proc Natl Acad Sci U S A. 1994 Nov 22;91(24):11660-4. doi: 10.1073/pnas.91.24.11660.
Fluorescence resonance energy transfer (FRET) has been used to demonstrate the bending of DNA and RNA helices for three series of double-stranded molecules containing bulge loops of unopposed adenosine nucleotides (An, n = 0-9). Fluorescein and rhodamine were covalently attached to the 5' termini of the two component strands. Three different methods were applied to measure the FRET efficiencies. The extent of energy transfer within each series increases as the number of bulged nucleotides varies from 1 to 7, indicating a shortening of the end-to-end distance. This is consistent with a bending of DNA and RNA helices that is greater for larger bulges. The FRET efficiency for DNA molecules with A9 bulges is lower than the efficiency for the corresponding A7 bulged molecules, although the A9 molecules exhibit increased electrophoretic retardation. Ranges of bending angles can be estimated from the FRET results.
荧光共振能量转移（FRET）已被用于证明含有未配对腺苷核苷酸凸起环（An，n = 0 - 9）的三类双链分子中DNA和RNA螺旋的弯曲情况。荧光素和罗丹明共价连接到两条组成链的5'末端。应用了三种不同的方法来测量FRET效率。随着凸起核苷酸的数量从1变化到7，每个系列内的能量转移程度增加，表明端到端距离缩短。这与DNA和RNA螺旋的弯曲情况一致，即较大的凸起弯曲程度更大。具有A9凸起的DNA分子的FRET效率低于相应的A7凸起分子的效率，尽管A9分子表现出增加的电泳延迟。可以从FRET结果估计弯曲角度范围。
