Infrared and Raman studies show that poly(dA).poly(dT) and d(AAAAATTTTT)2 exhibit a heteronomous conformation in films at 75% relative humidity and a B-type conformation at high humidities and in solution.
Infrared and Raman studies show that poly(dA).poly(dT) and d(AAAAATTTTT)2 exhibit a heteronomous conformation in films at 75% relative humidity and a B-type conformation at high humidities and in solution.
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红外%20and%20Raman%20studies%20show%20that%20poly(dA).poly(dT)%20and%20d(AAAAATTTTT)2%20exhibit%20a%20heteronomous%20conformation%20in%20films%20at%2075%%20relative%20湿度
DOI：
10.1021/bi00386a017
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发表时间：
1987
期刊：
影响因子：
2.9
通讯作者：
Peticolas,WL
中科院分区：
文献类型：
--
作者：
Taillandier,E;Ridoux,JP;Liquier,J;Leupin,W;Denny,WA;Wang,Y;Thomas,GA;Peticolas,WL
摘要：用拉曼光谱和红外光谱研究了双链十脱氧核苷酸d（AAAAATTTTT）2和双螺旋多核苷酸poly（dA）、poly（dT）在不同环境条件下的光谱。已经拍摄了流延膜的IR光谱，并与交替聚（dA-dT）的IR光谱进行了比较，交替聚（dA-dT）在高（> 92%）和低（75%）相对湿度（RH）条件下显示出清晰的B属和A属振动光谱。红外光谱数据表明，在高含水量的薄膜中，d-（AAAAATTTTT）2和poly（dA）-poly（dT）分子均为B-属构象。当薄膜的相对湿度降低时，红外光谱反映了d（AAAAATTTTT）2和poly（dA）-poly（dT）的几何构型逐渐演变为介于B属和A属之间的中间构型，但没有得到纯A属的红外光谱。在这些DNA中，在75%RH下，腺苷的IR带与在75%RH下的poly（dA-dT）中发现的频率相同，其中局部呋喃糖构象是C3'内/反，但胸苷频率不类似于在75%RH下的poly（dA-dT），而是类似于在高湿度下的poly（dA-dT）。得出的结论是，聚（dA）-聚（dT）和d（AAAAATTTTT）2在低湿度下的流延膜中采用完全异规的双重几何结构。对于水溶液中的研究，采用了拉曼效应。作为溶液中的异规构象的模型，使用双链聚（rA）-聚（dT）。设计了两种方法来估计溶液中d（AAAAATTTTT）2和poly（dA）-poly（dT）的异规构象的量，所述异规构象的量由糖-磷酸盐带和腺嘌呤带的强度获得，所述糖-磷酸盐带和腺嘌呤带通过将拉曼光谱拟合到Lorentzians带的总和。这些测量表明，在拉曼效应的时间尺度上，约30%的腺嘌呤残基以C3 '-内/反构象连接到呋喃糖环上。这意味着双链体中不超过约15%的呋喃糖环处于这种构象。如果聚（dA）-聚（dT）的构象在溶液中快速波动，则这种少量的C3 ′-内环褶皱可能难以通过其他技术如NMR检测。已知DNA和合成的寡核苷酸或多核苷酸的三个主要双螺旋家族，A、B和Z家族，其特征在于各种物理技术，X射线晶体或纤维衍射，NMR，振动光谱（IR和拉曼）和圆二色性。近年来，许多研究致力于确定DNA的几何结构，因为序列依赖性的结构变异可以作为核酸生物学功能的启动信号。
Revised Manuscript Received January 29, 1987 abstract: The decadeoxynucleotide d (AAAAATTTTT) 2 in duplex form and the double-helical poly-nucleotide poly (dA> poly (dT) have been studied byRaman and infrared (IR) spectroscopy under a variety of environmental conditions. The IR spectra have been taken of cast films and compared to the IR spectra of the alternating poly (dA-dT), which shows clear B-genus and A-genus vibrational spectra under conditions of high (> 92%) and low (75%) relative humidity (RH). From the IR data, it is shown that d-(AAAAATTTTT) 2 and poly (dA)-poly (dT) adopt a B-genus conformation in films with high water content. When the relative humidity of the film is decreased, the IR spectra reflect a gradual evolution of the geometry of both d (AAAAATTTTT) 2 and poly (dA)-poly (dT) into a form intermediate between the B genus and A genus, but the IR spectrum of a pure A genushas not been obtained. In these DNAs at 75% RH, the IR bands of adenosine have the same frequencies as those found in poly (dA-dT) at 75% RH where the local furanose conformation is C3'endo/anti, but the thymidine frequencies do not resemble those of poly (dA-dT) at 75% RH but rather those of poly (dA-dT) at high humidities. It is concluded that both poly (dA)-poly (dT) and d (AAAAATTTTT) 2 adopt a fully heteronomous duplex geometry in cast films at low humidity. For studies in aqueous solution the Raman effect was employed. As a model for the heteronomous conformation in solution, the duplex poly (rA)-poly (dT) was used. Two methods were devised to estimate the amount of heteronomous conformation for d (AAAAATTTTT) 2 and poly (dA)-poly (dT) in solution from the intensities of a sugar-phosphate band and an adenine band obtained by a fit of the Raman spectrum to a sum of Lorentzians bands. These measurements indicate that about 30% of the adenine residues were attached to furanose rings with the C3'-endo/anti conformation on the time scale of the Raman effect. This would mean that no more than about 15% of the furanose rings in the duplex are in this conformation. If the conformation of poly (dA)-poly (dT) is fluctuating rapidly in solution, this small amount of C3'-endo ring pucker might be difficult to detect by other techniques such as NMR.Three main double-helical families are known for DNAs and synthetic oligo-or polynucleotides, the A, B, and Z families characterized by various physical techniques, X-ray singlecrystal or fiber diffraction, NMR, vibrational spectroscopy (IR and Raman), and circular dichroism. Recently, many investigations have been undertaken to determine the detailed geometry of DNA of defined base sequence, because se-quence-dependent structural variations could serve as recog-nition signals in the biological functions of the nucleic acids.