Infrared spectrum of a DNA–RNA hybrid

✍ Scribed by Shigesada Higuchi; Masamichi Tsuboi; Yoichi Iitaka

• Publisher: Wiley (John Wiley & Sons)
• Year: 1969
• Tongue: English
• Weight: 456 KB
• Volume: 7
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1969.360070606

✦ Synopsis

The infrared absorption spectrum in the 4000-400 cm-1 region of an oriented film of a DNA-RNA hybrid in its undeuterated and deuterated states was observed with the polarized radiation. Most of the stronger bands found in the double-helical DNA's and doublehelical RNA's are identified in the spectrum of the hybrid. The absorption band at 1225 cm-1 shows a perpendicular dichroism and that at 1085 cm-1 shows almost no dichroism. These facts indicate that the orientation of the P /' group with respect to the helix axis in the hybrid structure is not entirely the same as that in the double-helical Na DNA at 75% RH., although the x-ray diffraction pattern of the hybrid is quite similar to that of the DNA A form. The POZorientation is not the same as that in the double-helical RNA either. The observed dichroism is explained, however, by considering that the PO2group in the RNA moiety takes nearly the same orientation as that in the double-helical RNA, and the POzgroup in the DNA moiety takes nearly the same as that in the double-helical DNA.