SEQUENCE DEPENDENCE OF THE CIRCULAR-DICHROISM OF SYNTHETIC DOUBLE-STRANDED RNAS
SEQUENCE DEPENDENCE OF THE CIRCULAR-DICHROISM OF SYNTHETIC DOUBLE-STRANDED RNAS
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DOI：
10.1002/bip.1981.360200702
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发表时间：
1981-01-01
期刊：
影响因子：
2.9
通讯作者：
ALLEN, FS
中科院分区：
文献类型：
--
作者：
GRAY, DM;LIU, JJ;ALLEN, FS
五种新的双链RNA聚合物，Poly[r(A-G).cntdo.R(C-U)]，聚[r(A-U-C).R(G-A-U)]，聚[r(A-C-U).R(A-G-U)]，聚[r(A-A-C).R(G-U-U)]和Poly[r(A-C-C).cntdo.R(G-G-U)，并用圆二色谱(CD)对其进行了表征。与以前发表的7个其他RNA序列的谱一起，这些新序列的谱提供了一个足以近似第一邻公式的所有其他RNA序列的谱的库，此外，还给出了4个谱，可以用它们来检验第一邻近似的有效性。RNA序列异构体的光谱有很大的不同，但光谱基本上遵循第一邻域关系。对CD谱中约295和210 nm处的负带进行了初步的第一近邻指认。光谱独立性测试表明，在12个聚合物光谱中，至少有7个显著的独立光谱形状，比对未知RNA序列的第一邻近频率进行最准确的光谱分析所需的8个光谱形状少了一个。计算随机碱基组成的RNA的光谱，近似于具有复杂序列的天然RNA。分配给第一邻近碱基对的光谱分量的T矩阵从10个光谱中得到。该矩阵允许估计任何其他已知RNA序列的CD谱或分析未知序列的谱以获得其第一邻近碱基对频率的分布。对两种合成聚合物和两种天然RNA的测试分析对使用该T矩阵的第一近邻频率确定的准确性设置了可能的限制。总结了所有RNA和相应DNA序列的熔融温度；DNA和RNA的Tm[熔化温度]值近似服从第一邻域关系。
Five new double-stranded RNA polymers, poly[r(A-G) .cntdot. r(C-U)], poly[r(A-U-C) .cntdot. r(G-A-U)], poly[r(A-C-U) .cntdot. r(A-G-U)], poly[r(A-A-C) .cntdot. r(G-U-U)] and poly[r(A-C-C) .cntdot. r(G-G-U)], were synthesized and studied by circular dichroism (CD). Together with previously published spectra of 7 other RNA sequences, the spectra of these new sequences provide a library sufficient to approximate the spectra of all other RNA sequences of first-neighbor formulas and, in addition, give 4 spectra with which the validity of first-neighbor approximations may be tested. The spectra of RNA sequence isomers are very different, but the spectra essentially do obey first-neighbor relationships. Tentative first-neighbor assignments of negative bands at about 295 and 210 nm in the CD spectra were derived. A test spectral independence shows that among the 12 polymer spectra there are at least 7 significant independent spectral shapes, one less than the 8 needed to give the most accurate spectral analysis of an unknown RNA sequence for its first-neighbor frequencies. Spectra are calculated for RNA of random base composition, approximating natural RNA having complex sequences. A T-matrix of spectral components assigned to the first-neighbor base pairs is derived from 10 of the spectra. This matrix allows an estimation of the CD spectrum of any other known RNA sequence or an analysis of the spectrum of an unknwon sequence for its distribution of first-neighbor base-pair frequencies. Test analyses of 2 of the synthetic polymers and of 2 natural RNA set a probable limit on the accuracy of first-neighbor frequency determinations using this T-matrix. The melting temperatures for all the RNA and corresponding DNA sequences are summarized; the Tm [melting temperature] values of both DNA and RNA approximately obey first-neighbor relationships.