ARTICLE

ELECTRON STAINS : I. Chemical Studies on the Interaction of DNA with Uranyl Salts

C. Richard Zobel Ph.D.¹ and Michael Beer Ph.D.¹

¹ From the Department of Biophysics, Johns Hopkins University, Baltimore

Chemical studies have been carried out on the interaction of DNA with uranyl salts. The effect of variations in pH, salt concentration, and structural integrity of the DNA on the stoichiometry of the salt-substrate complex have been investigated. At pH 3.5 DNA interacts with uranyl ions in low concentration yielding a substrate metal ion complex with a UO₂⁺⁺/P mole ratio of about and having a large association constant. At low pH's (about 2.3) the mole ratio decreases to about . Destruction of the structural integrity of the DNA by heating in HCHO solutions leads to a similar drop in the amount of metal ion bound. Raising the pH above 3.5 leads to an apparent increase in binding as does increasing the concentration of the salt solution. This additional binding has a lower association constant. Under similar conditions DNA binds about seven times more uranyl ion than bovine serum albumin, indicating useful selectivity in staining for electron microscopy.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Miyoshi, K., Shillingford, J. M., Smith, G. H., Grimm, S. L., Wagner, K.-U., Oka, T., Rosen, J. M., Robinson, G. W., Hennighausen, L. (2001). Signal transducer and activator of transcription (Stat) 5 controls the proliferation and differentiation of mammary alveolar epithelium. JCB 155: 531-542 [Abstract] [Full Text]  

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents