Local Raman Tensors of Double-Helical DNA in the Crystal: A Basis for Determining DNA Residue Orientations

James M. Benevides, Masamichi Tsuboi, George J. Thomas, Andrew H.J. Wang

研究成果: 雜誌貢獻文章同行評審

31 引文 斯高帕斯(Scopus)

摘要

We report the first experimental determination of Raman scattering tensors for localized base and sugar-phosphate vibrations of double-helical DNA. Argon-laser excitation was employed in combination with a multichannel Raman microscope system to measure polarized Raman scattering intensities from oriented single crystals of d(CGCGCG) in the left-handed Z conformation. The Raman measurements were made on crystals of dimensions abc = 30 × 50 × 70 μm in space group P212121, for which the three-dimensional structure has been solved by X-ray methods.1,2 For each intense band in the 300–1700-cm−1 interval of the Raman spectrum, we determined the relative scattering intensities, Iaa, Ibb, and Icc, corresponding to the aa, bb, and cc components of the crystal Raman tensors. The tensor quotients from the crystal were augmented with measured depolarization ratios of analogous Raman bands in the solution isotropic form of Z-DN A and its nucleotide constituents. From these data, we have calculated the shapes and orientations of localized, vibration-specific, Raman scattering tensors applicable to normal modes of the bases (625 (dG), 670 (dG), 784 (dC), 1264 (dC), 1318 (dG), 1486 (dG), and 1579 (dG) cm−1), phosphate-ester moieties (749, 796, 868, and 1095 cm−1), and furanose substituents (1426 and 1433 cm−1). The results differentiate normal modes with polarizability changes in the planes of the bases (dC or dG), from those perpendicular to the base planes, and along specific bond-angle bisectors (OPO, HCH). These findings provide a basis for future applications of Raman microscopy as a probe of DNA orientation and anisotropy in biological complexes.

原文英語
頁(從 - 到)5351-5359
頁數9
期刊Journal of the American Chemical Society
115
發行號13
DOIs
出版狀態已發佈 - 6月 1 1993
對外發佈

ASJC Scopus subject areas

  • 催化
  • 化學 (全部)
  • 生物化學
  • 膠體和表面化學

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