Characterization of acid-denatured DNA by low-angle light scattering

✍ Scribed by Alvin I. Krasna; Jeffrey R. Dawson; Jerry A. Harpst

• Publisher: Wiley (John Wiley & Sons)
• Year: 1970
• Tongue: English
• Weight: 653 KB
• Volume: 9
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1970.360090905

✦ Synopsis

Abstract

Low‐angle light scattering results reported previously demonstrated that measurements on high molecular weight native DNA must be made at angles below 30° in order to obtain correct molecular weights. Earlier light‐scattering data obtained on denaturated DNA at angles above 30° showed no change in molecular weight upon denaturation, even though other techniques clearly showed that strand separation occurred. This paper reports low‐angle measurements on solutions of calf thymus and T7 DNA denatured under acidic conditions. The results demonstrate that a halving of molecular weight consistent with strand separation is detected by light scattering only when low‐angle data are used to obtain correct molecular weights for native material. As expected from theoretical considerations, the scattering from denatured DNA is a linear function of sin^2^(θ/2), where θ is the angle of observation. This result shows that anticipated experimental artifacts have no significant effect on the low‐angle measurements and demonstrates that the curvature in the scattering envelope observed for native DNA below 30° is an inherent property of the native molecule.